In early studies, it was found that ruminants have a unique complex digestive and metabolic system, the abomasum and intestinal digesta empties are significantly different from those of monogastric animals. However, limited by research methods, few studies have been carried out on the composition of digesta, gastrointestinal digestive enzymes, microbial composition and the nutrients digestion in the rumen. In subsequent studies, the role of rumen in ruminants has been highly valued, while the role of other parts of digestive tract, especially the abomasum and intestines, in nutrients digestion and metabolism has been neglected for a long time. Since then, limited studies have shown that the digestive tract after the rumen may play a crucial role in nutrient metabolism, especially with the development of high-concentrate fattening technology for beef cattle, this importance is increasing. The author believes that taking the nutrient metabolism of different digestive parts of ruminants into consideration as a whole and establishing the whole digestive tract nutrient regulation theory will be more in line with the needs of ruminant nutrition research and will be more targeted to guide the production of ruminants. At present, the priority of research should be to explore the digestive tract nutrient metabolism of nutrients in the post-rumen digestive tract, and how different parts of the digestive tract cooperate to achieve nutrient digestion and metabolism.

China’s soybean imports are about 100 million tons per year, about 90% of which are used for animal husbandry, so soybeans are highly dependent on imports and seriously limit the sustainable development of animal husbandry, and exploring efficient feed ingredients to reduce the dependence of soybean imports is one of the effective ways on replacing soybeans, leading to reduce the dependence of soybean imports. Cottonseed meal is the third largest protein feed ingredients in the world, after soybean meal and rapeseed meal, but the high free gossypol content and unbalanced amino acid composition in cottonseed meal are the main factors to limit its application. It has great significance to improve the nutritional value of cottonseed processing by-products for achieve efficient substitution of soybean protein. With the development of cottonseed processing technology, technologies of using detoxification and desugaring method for extraction of gossypol and raffinose to produce cottonseed protein has gradually matured. The crude protein content of cottonseed protein is higher than 50%, and it has the advantages of balancing amino acid composition, high nutritional value and good palatability. In this paper, the nutritive composition of cottonseed protein and functional substances produced during processing are reviewed, and the application potential of cottonseed protein in piglets’ diet is discussed, aiming to provide theoretical support for improving the utilization efficiency of cottonseed protein and reducing the import of soybeans in pig production.

This experiment aimed to investigate the effects of medium-chain fatty acids (MCFA) on growth performance, diarrhea, nutrient apparent digestibility and serum indexes of weaned piglets. Three hundred 29-day-old weaned piglets (Duroc×Landrace×large cross) with similar body weight [(6.83±0.44) kg] were randomly divided into 4 groups with 3 replicates per group and 25 pigs per replicate. The control group was fed a basal diet, and the experimental groups were fed the basal diets supplemented with 1, 2 or 4 g/kg MCFA, respectively. The experiment lasted for 35 days including a 5-day transition period. The results showed as follows: compared with the control group, dietary adding MCFA with different doses decreased the fecal score and diarrhea rate of piglets (P<0.05). Compared with control group, the apparent digestibility of ether extract of piglets fed 4 g/kg MCFA was higher (P<0.05). Piglets fed 4 g/kg MCFA had lower serum malondialdehyde content (P<0.05) and trended higher serum superoxide dismutase activtiy (0.05<P<0.10) compared with control group. Compared with control group, dietary adding MCFA with different doses increased serum immunoglobulin A content (P<0.05). Compared with control group, adding 1 and 2 g/kg MCFA trended to increase serum immunoglobulin M content (0.05<P<0.10). In conclusion, MCFA can enhance antioxidant capacity and immune ability, relive diarrhea and weaning stress in weaned piglets. However, this experiment find that it can not promote weight gain and improve feed utilization rate.

Vitamin B₆ is an essential micronutrient for the healthy growth and normal physiological function of animals. It not only participates in the normal metabolic reaction of the body as a coenzyme, but also has a variety of biological functions such as neuromodulation, antioxidant, anti-inflammatory, immunomodulatory and anti-tumor. Low plasma vitamin B₆ level status is strongly associated with higher risk of a variety of inflammatory disease. The inverse association is thought to be the result of mobilization of vitamin B₆ to the site of inflammation, for use of regulation of tryptophan and sphingolipid metabolism, modulation of lymphocyte trafficking, number and function, and inhibition of inflammatory signaling pathway, to exert their immunomodulatory and anti-inflammatory properties. This article reviewed the biological functions, potential anti-inflammatory mechanism and application in feed of vitamin B₆, in order to provide reference for the application of vitamin B₆ in animal husbandry.

Fat deposition in pigs is influenced by many factors such as genetics, diet, feeding management and gut microbiota. Fat deposition is an important economic trait, and excessive fat deposition affects carcass quality and feed utilization. More and more studies have shown that gut microbiota plays an important role in host fat deposition. In this paper, the composition of pig gut microbiota community was first summarized. And then, the gut microbial taxa that have been identified so far to affect the fat deposition in pigs were systematically summarized. The possible mechanism of the gut microbiota affecting host fat deposition was also reviewed. According to the current research progress all over the world, this paper induced the progress on the methods to improve host fat deposition by regulating the gut microbial composition, and briefly looked ahead the possible research direction in this area in the future. This review provides a reference for reducing fat deposition and increasing lean meat percentage in pigs by regulating gut microbiota in the future.

Rosemary is a plant shrub that belongs to Dicotyledoneae, Labiaceae and Rosmarinus. Rosemary extracts, including rosemary essential oil, carnosic acid, oleanolic acid, ursolic acid, rosmarinic acid and so on, which contains various functional chemical substances, such as flavonoids, terpenoids, phenolic acids, lipids and so on. Therefore, it plays a positive role in antioxidant, anti-inflammatory, anti-tumor, bacteriostatic, insecticidal and so on. Therefore, this research mainly reviewed the biological functions of rosemary extracts, the effects of rosemary extracts on growth, immune, antioxidant and meat quality of animal and their related mechanism, in order to provide reference for the application of rosemary extract in the healthy breeding of animals.

At present, the energy system in the diet is mainly formulated based on net energy (NE), and other amino acids are balanced according to the standard ileal digestible lysine (SID-Lys). Too much or too little SID-Lys/NE in the diet has adverse effect on pig performance, economic profitability and environment. Therefore, it is important to accurately formulate SID-Lys/NE that meets the nutritional requirement of pigs. This article reviewed the effects of different SID-Lys/NE on pig performance and provide reference for reasonable optimization of formula.

The aim of this study was to investigate the effects of plant essential oil compounds on growth performance, organ indexes, nutrient apparent digestibility, serum biochemical and antioxidant indexes and intestinal morphology of weaned piglets. A total of 120 healthy 28-day-old “Duroc×Landrace×Large White” crossbred weaned piglets with an initial body weight of (8.54±0.63) kg were randomly assigned to 5 groups with 6 replicates per group and 4 piglets per replicate. Piglets in the control group (CON group) were fed a basal diet, piglets in the antibiotic group (AGP group) were fed a basal diet supplemented with 75 mg/kg chlortetracycline, and the others in experimental groups were fed basal diets supplemented with 50 (CP250 group), 500 (CP500 group) and 750 mg/kg (CP750 group) plant essential oil compounds, respectively. The experiment lasted for 35 days. The results showed as follows: 1) compared with the CON group, the final body weight and average daily gain of AGP, CP250 and CP500 groups were significantly increased (P<0.05), and the feed to gain ratio of CP250 group was significantly decreased (P<0.05). 2) Compared with the CON and AGP group, the liver and kidney indexes of CP500 group were significantly increased (P<0.05). 3) Compared with the CON group, the apparent digestibility of gross energy, crude protein and organic matter of CP250 group was significantly increased (P<0.05); compared with the AGP group, the ether extract apparent digestibility of CP250 group was significantly increased (P<0.05). 4) Compared with the CON group, the contents of urea nitrogen and total cholesterol in serum of AGP, CP250, CP500 and CP750 groups were significantly decreased (P<0.05), and the serum glucose content was significantly increased (P<0.05); the serum total protein content of AGP, CP250 and CP500 groups was significantly increased (P<0.05). 5) Compared with the CON group, the serum total-superoxidase dismutase activity of CP500 and CP750 groups was significantly increased (P<0.05), and the serum malondialdehyde content of AGP, CP250 and CP500 groups was significantly decreased (P<0.05). 6) Compared with the CON group, the jejunum villus height of AGP, CP250 and CP500 groups was significantly increased (P<0.05), and the jejunum villus height/crypt depth of AGP, CP250, CP500 and CP750 groups was significantly increased (P<0.05). In conclusion, dietary plant essential oil compounds supplementation can improve the growth performance of weaned piglets, promote the digestion and absorption of nutrients, regulate the body metabolism, and improve the antioxidant capacity and intestinal morphology, which have similar effects to antibiotic growth promoters. Under this experimental condition, the dietary optimal supplemental level of plant essential oil compounds for weaned piglets is 250 mg/kg.

Digestive tract is not only the main place for nutrient digestion and utilization of ruminants, but also an important part of the body’s immune system. Dietary structure not only significantly affects the pattern of nutrient digestion and utilization in digestive tract, but also significantly affects the structure and function of digestive tract. In this paper, the immune composition and nutrient redistribution of digestive tract in ruminants under immune activation were reviewed, aiming to provide reference for systematic regulation of digestive tract health of ruminants and improvement of animal welfare and performance.

The intestinal barrier is not only a structural basis for selective digestion and absorption of nutrients, but also a protective barrier for the intestinal tract to continuously receive external stimuli. Sodium butyrate can maintain the integrity of intestinal mucosal epithelium, enhance intestinal immune function, reduce intestinal inflammation and maintain intestinal microbiota balance by regulating histone acetylation, G protein-coupled receptor and other pathways, so as to play the role of disease resistance and growth promotion. This review summarized the mechanism of sodium butyrate regulating intestinal barrier and its application in broiler breeding, in order to provide references for sodium butyrate to replace antibiotics in broiler nutrition.

n-6 polyunsaturated fatty acids are essential fatty acids for animals, which are closely related to lipid metabolism, immune function and reproductive performance. Many studies have shown that dietary supplementation of n-6 polyunsaturated fatty acids can not only promote the establishment of cow pregnancy and increase the conception rate, but also benefit fetal development, postnatal offspring health and growth performance, and improve the performance and meat quality of finishing cattle. In view of this, this paper reviewed the physiological functions of n-6 polyunsaturated fatty acids and elaborates on their application in beef cattle production, aiming to provide theoretical references for the scientific and reasonable application of n-6 polyunsaturated fatty acids to improve the reproductive function, health, and performance of beef cattle.

Colibacillosis always plagues poultry production and causes huge economic losses to the poultry industry. When poultry infected with Escherichia coli, they show many diseases such as peritonitis, septicemia and pericarditis, which lead to decrease of performance and even death. Therefore, alleviating avian colibacillosis is an urgent problem to be solved. In this paper, we reviewed the harmful effect of pathogenic Escherichia coli in poultry, and the underlying regulation mechanism of phytogenic feed additives alleviating avian colibacillosis, in order to provide theoretical basis for the prevention and treatment of avian colibacillosis in poultry production.

The synergistic fermentation of bacteria and enzymes can increase the degradation efficiency of fiber and anti-nutritional factors in feed ingredients, improve fermentation quality and palatability, and play a positive role in the growth and intestinal health of livestock and poultry. This review introduced the degradation mechanism of plant fiber and the types of fiber-degrading enzymes produced by fungi and bacteria, and summarized the application effects of synergistic fermented feeds of bacteria and enzymes in animal production, in order to provide reference for further exploring the synergistic fermentation mechanism of bacteria and enzymes.

Intestine is one of the important internal organs of pigs, which is crucial to their quality of life. In the study of intestine, intestinal barrier has always been an important research field. The intestinal barrier consists of multiple layers of complex structures, including intestinal epithelial cells and the tight connections between them, the mucus layer covered by the epithelial cells, the symbiotic microorganisms colonized in the mucus, and other immune-related components, which support each other and work together. The intestinal mucus layer is the link of the intestinal barrier, which can isolate pathogens from the intestinal epithelium, reduce the mechanical friction of food debris or chyme, promote the healing of the damaged intestinal epithelium, provide the reaction conditions for the immune active substances in the intestine, and provide energy and colonization sites for symbiotic microorganisms. In this paper, we reviewed the composition and function of intestinal mucus layer in pigs, discussed the regulation of intestinal mucus barrier on immune function of piglets, constipation in late pregnancy of sows and intestinal flora composition, and discussed the regulatory effects of dietary nutrients on intestinal mucus barrier in pigs, aiming to clarify the importance of mucus barrier regulation in intestinal health of pigs.

Hot red pepper contains many active ingredients, such as capsanthin and capsaicin etc. It has been proven that hot red pepper and capsaicin not only enhance the feed intake of poultry, improve the performance and egg quality of poultry. In addition, hot red pepper and capsaicin play important roles in improving the body antioxidant capacity, regulating lipid metabolism and intestinal microbial community, and promoting follicular development. Therefore, this paper summarized the research progress of the biological functions of hot red pepper and capsaicin and their applications in poultry production, in order to provide references for the usage of hot red pepper and capsaicin in poultry production.

Lactobacillus plantarum is a kind of common lactic acid bacteria, widely found in the gastrointestinal tract of humans and animals, fermented products and other environments, and can be used in poultry industry due to its good gastrointestinal tolerance, high adhesion ability, broad spectrum bacteriostasis and so on. In this paper, the physiological functions of Lactobacillus plantarum were elaborated, and the application research progress of Lactobacillus plantarum in poultry production was summarized from aspects of improving production performance, enhancing immunity and resistance to disease, improving oxidation performance and lipid metabolism, and maintaining the homeostasis of intestinal flora. The aim of this paper was to provide certain theoretical basis and research ideas for the research and application of Lactobacillus plantarum in poultry.

Probiotics as feed additives used in poultry production have become one of the alternative measures. In this paper, the mechanism of probiotics on inhibiting pathogen infection, enhancing antioxidant capacity, alleviating toxicity and improving intestinal environment in poultry production were reviewed, and the application effect of probiotics in poultry production were described, and the screening criteria of probiotics were summarized, in order to provide reference for reasonable application of probiotics in poultry production.

Wheat is the third largest grain crop in China, and its crude protein content and limiting amino acid contents such as lysine and methionine are higher than corn, which has a good application prospect in pigs’ diets. However, non-starch polysaccharides such as arabinoxylan and β-glucan and phytic acid in wheat have negative effects on the digestion and utilization of nutrients. Therefore, this paper mainly introduced the anti-nutrition factors in wheat and their anti-nutrition mechanism and expounded the principle and research progress of improving wheat feeding value with enzyme preparation and physical and biological processing technologies. It is expected to further promote the understanding of wheat for feedstuff enterprise and provided a reference for formulating pigs’ diets reasonably.

This experiment was conducted to investigate the effects of different supplemental levels of amino acid chelated iron on growth performance, blood indices, liver iron deposition and meat quality traits of growing-finishing pigs. A total of 216 healthy “Duroc×Landrace×Yorkshire” crossbred pigs with an average body weight of (24.10±2.43) kg were randomly divided into 6 groups with 6 replicates per group and 6 pigs per replicate (half male and half female). Pigs in the control group (blank control) were fed a basal diet without any iron additive, those in FeSO₄ group (positive control) were fed the basal diet supplemented with 60 mg/kg FeSO₄ (calculated as iron), and those in the other 4 experimental groups were fed the basal diet supplemented with 15, 30, 45 and 60 mg/kg amino acid chelated iron (all calculated as iron), respectively. The experiment lasted for 110 days, and the pigs were divided into three growth stages according to the body weight of 25 to 50 kg, 51 to 85 kg and 86 to 120 kg. The results showed as follows: 1) compared with the control group and FeSO₄ group, different supplemental levels of amino acid chelated iron had no significant effects on growth performance of pigs at each body weight stage and the whole experiment period (P>0.05). However, the average daily gain (ADG) was linearly increased with the increase of amino acid chelated iron supplemental level in 86 to 120 kg stage and the whole experiment period (P<0.05). 2) At 50 kg, compared with the control group, the supplementation of 30, 45 and 60 mg/kg amino acid chelated iron extremely significantly increased the mean corpuscular hemoglobin (MCH) content and mean corpuscular volume (MCV) in blood of experimental pigs (P<0.01); at 85 kg, compared with the control group, the supplementation of 30, 45 and 60 mg/kg amino acid chelated iron significantly or extremely significantly increased the hemoglobin (HGB) content (P<0.05), MCH content (P<0.01) and MCV (P<0.01) in blood; at 120 kg, compared with the control group, the supplementation of 30, 45 and 60 mg/kg amino acid chelated iron extremely significantly increased MCH content in blood (P<0.01), and the supplementation of 45 and 60 mg/kg amino acid chelated iron extremely significantly increased MCV in blood (P<0.01). At the same time, with the increase of amino acid chelated iron supplemental level, the MCH content and MCV in blood of experimental pigs in each body weight stage showed linear increase and quadratic change (P<0.01). In addition, except for the 15 mg/kg amino acid chelated iron supplemental group, there was no significant difference in blood routine indices between the other amino acid chelated iron supplemental level groups and FeSO₄ group (P>0.05). 3) Compared with the control group, the liver iron content of growing-finishing pigs was extremely significantly increased by different supplemental levels of amino acid chelated iron (P<0.01), which was linearly increased and changed quadratically with the increase of amino acid chelate iron supplemental level (P<0.01). Compared with FeSO₄ group, the supplementation of 60 mg/kg amino acid chelated iron extremely significantly increased the liver iron content (P<0.01). 4) Compared with the control group, the supplementation of 45 and 60 mg/kg amino acid chelated iron significantly or extremely significantly increased the color redness (a^*) value (P<0.05) and saturation Chroma (c^*) value (P<0.01) in longissimus dorsi muscle of growing-finishing pigs, and with the increase of amino acid chelated iron supplemental level, they both showed linear increase and quadratic change (P<0.05). In conclusion, the supplementation of 15 mg/kg amino acid chelated iron can effectively promote iron deposition in liver of growing-finishing pigs, the supplementation of 30 mg/kg amino acid chelated iron can effectively promote hemoglobin synthesis in blood, and the supplementation of 45 mg/kg amino acid chelated iron can improve meat color. These results indicate that the amino acid chelated iron used in this experiment is an efficient source of feeding iron in pigs.

Single cell protein (SCP) consists mainly of the cells of microorganisms, which is a protein-rich mixture. As a new feed protein resource, it has the advantages of low raw material price, not occupying more cultivated land and water, being able to carry out industrial mass production, and has high nutritional value. SCP is a research hotspot in the field of alternative proteins. In this paper, the research direction and progress of SCP in recent years were summarized from the microbial species, the available cheap raw materials, and the application value of SCP in feed, and the main problems existing in current production and solutions were discussed in order to provide a theoretical basis for the production and application of SCP.

In recent years, studies have pointed out that free radical homeostasis and oxidative stress are important causes of animal lesions. Therefore, it is very important to develop safe and efficient animal health gain products. Lactic acid bacteria are recognized as food-grade probiotics, and their unique antioxidant activity has been confirmed, which has great potential in the development and utilization of antioxidants in livestock and poultry, and can be used as antioxidant microecologics to alleviate oxidative stress and its complications in livestock and poultry. This paper not only summarizes the research and application of antioxidants, but also reviews the mechanism and evaluation methods of antioxidant activities of lactic acid bacteria in the field of livestock and poultry. It aims to provide reference for the research and development of new micro-ecological antioxidants in the field of animal husbandry and further research on antioxidant activities of lactic acid bacteria.

Intestinal bacteria produce a variety of metabolites that play an important role in the regulation of animal intestinal health and physiological homeostasis. Indole propionic acid (IPA) is an indole derivative derived from the bacterial metabolism of tryptophan in the gut, which has antioxidant, anti-inflammatory and immunomodulatory effects, has been extensively researched in the prevention and treatment of metabolic and neurological diseases. Recently, several studies have reported that IPA has a positive effect on intestinal health by regulating the structure of intestinal bacteria, improving intestinal barrier function and enhancing intestinal immunity, and is expected to be developed and applied as a novel green feeding additive. This article reviews the physicochemical property, synthetic and metabolic characteristics of IPA, as well as its main mechanisms of regulating animal intestinal health, to provide reference for the application of IPA in regulating animal intestinal health and preventing or treating intestinal diseases.

Isoflavones are a class of polyphenol compounds with 3-benzopyrone as the parent nucleus and structurally similar to estrogen. Isoflavones can regulate the physiological functions of animal by improving the antioxidant capacity, alleviating the inflammation and playing the role of estrogen. Moreover, isoflavone metabolic derivatives have higher bioavailability and activity in animals. This paper reviewed the metabolic process of isoflavones, the biological functions and the research progress in livestock and poultry production of isoflavones and their metabolic derivatives, aiming to further promote the application of isoflavones and their metabolic derivatives in livestock and poultry production.

The purpose of this experiment was to study the effects of dietary Clostridium butyricum on cecal flora structure and fecal short chain fatty acids (SCFAs) contents of Ira rabbits. A total of 216 weaned male Ira rabbits at 28 days of age with similar body weight were randomly divided into 4 groups with 6 replicates in each group and 9 rabbits in each replicate. The control group (CG group) was fed a basal diet, and the experimental groups were fed basal diets supplemented with 200 (LC group), 400 (MC group) and 600 mg/kg (HC group) Clostridium butyricum, respectively. The pre-experimental period lasted for 4 days, and the experimental period lasted for 35 days. The results showed as follows: 1) the dominant bacteria in caecum in all groups were Firmicutes, Bacteroides, Verrucomicrobia and Actinobacia. 2) At 32 and 39 days of age, the cecal Actinobacia relative abundance of MC group was significantly lower than that of CG group (P<0.05). At 60 and 67 days of age, the cecal Verrucomicrobia relative abundance of LC, MC and HC groups was significantly lower than that of CG group (P<0.05). 3) At 53 and 67 days of age, the content of acetic acid and propionic acid in feces of experimental groups were increased compared with CG group. At 53 days of age, the fecal butyric acid content of LC group was significantly lower than that of CG group (P<0.05); at 67 days of age, the fecal isovaleric acid of LC group was significantly lower than that of CG group (P<0.05). 4) At 53 days of age, the Bacteroides relative abundance was significant positively correlated with the acetic acid content (P<0.05); the Ruminococcaceae_UCG-013 relative abundance was significant negatively correlated with the propionic acid content (P<0.05), and extremely significant negatively correlated with the butyric acid content (P<0.01). At 67 days of age, the Ruminococcaceae_NK4A214_group relative abundance was significant negatively correlated with the acetic acid content (P<0.05), and the Ruminococcaceae_UCG-013 relative abundance was significant negatively correlated with the propionic acid and butyric acid contents (P<0.05). To sum up, dietary Clostridium butyricum can change the cecal flora structure and microbial diversity, change the fecal SCFAs contents, and the cecal flora relative abundance is correlated with the fecal SCFAs contents.

This experiment was conducted to investigate the effects of different feeding time under restricted feeding conditions on carcass quality, meat quality and serum biochemical indices of finishing pigs. Thirty healthy three-way crossbred weaned piglets with similar body weight [(10.11±0.10) kg] were randomly divided into 3 groups (10 replicates in each group and 1 piglet in cah replicate): group A (feeding for 5 months), group B (feeding for 6 months) and group C (feeding for 7 months). The feed intake was controlled to 85% and 80% of group A, respectively, the 3 groups started at different time, when the average weight of experimental pigs in 3 groups reached 120 kg, slaughtered at the same time. The results showed that compared with the group A: 1) the average daily gain and average daily feed intake of groups B and C were significantly decreased (P<0.05), the carcass straight length was significantly increased (P<0.05); the backfat thickness of group B was significantly decreased (P<0.05); the longissimus dorsi redness (a^*) value at 45 min after slaughter of groups B and C was significantly increased (P<0.05), and the brightness (L^*) value was significantly decreased (P<0.05); 2) the serum urea nitrogen content of group B was significantly decreased (P<0.05), the contents of total protein, albumin, glucose, cholesterol, low density lipoprotein cholesterol and free fatty acid in serum of group C were significantly decreased (P<0.05), and the serum high-density lipoprotein cholesterol content of groups B and C was significantly increased (P<0.05); 3) the taste strength value of sweet amino acids, such as serine, glycine and arginine in longissimus dorsi of group B was significantly increased (P<0.05), and the taste strength value of bitter amino acid, such as phenylalanine in longissimus dorsi of groups B and C was significantly decreased (P<0.05); 4) the proportions of C18∶3n3 and C20∶2 in longissimus dorsi of group B were significantly increased (P<0.05), and the proportions of C18∶3n3, C20∶2, C22∶6n3 and total n-3 polyunsaturated fatty acids in longissimus dorsi of group C were significantly increased (P<0.05); 5) the glucose content and porcine hexokinase activity in longissimus dorsi of groups B and C were significantly increased (P<0.05), the glycolysis potential and glycogen content in longissimus dorsi of group C were significantly decreased (P<0.05), and the mRNA expression level of myosin heavy chain Ⅰ in longissimus dorsi of groups B and C was significantly increased (P<0.05). In conclusion, the longissimus dorsi fatty acid composition, muscle fiber type and meat quality of finishing pigs can be improved by extending the feeding time to 7 months under restricted feeding conditions, but the growth performance can be decreased, it increases the cost of making meat to some extent.

The aim of this study was to investigate the effects of classical music on slaughter performance and intestinal development of broilers chickens with different stocking densities. The experiment was conducted in a 2×3 factorial design (with/without music stimulation×3 stocking densities). Classical music was played in the group with music stimulation, and the three stocking density levels were 15.5, 17.9 and 20.3 birds/m², respectively. A total of 540 Cobb broilers of 1-day-old were randomly divided into 6 groups with 6 replicates per group. The experiment lasted for 42 days. The results showed as follows: 1) with the increase of stocking density, the live weight before slaughter, dressing percentage and pectoral muscle percentage of broilers were significantly decreased (P<0.05), and playing classical music significantly increased the live weight of broilers before slaughter (P<0.05). 2) Exposure to classical music had a tendency to increase the relative length of jejunum (P=0.088) and ileum (P=0.057) of broilers. 3) With the increase of stocking density, the villus height and villus height to crypt depth ratio (V/C) in duodenum, jejunum and ileum of broilers were significantly decreased (P<0.05), and the crypt depth in jejunum and ileum were significantly increased (P<0.05). Playing classical music significantly increased the villus height in jejunum of broilers (P<0.05), and had a tendency to decrease the V/C in jejunum (P=0.058) and ileum (P=0.080). Playing classical music significantly increased the V/C in ileum broilers with high stocking density (20.3 birds/m²) (P<0.05). 4) Increasing stocking density significantly decreased the relative abundances of uncultured_bacterium_f_Ruminococcaceae and Fecalibacterium in cecum of broilers (P<0.05). Playing classical music had no significant effects on cecal microflora of broilers (P>0.05). In conclusion, under the cage condition of this experiment, the stocking density of 20.3 birds/m² leads to the decrease of live weight before slaughter, slaughter percentage and pectoral muscle percentage of Cobb broilers, results in the imbalance of intestinal morphology and microflora, and the recommended stocking density is 17.9 birds/m². However, classical music stimulation can improve the live weight before slaughter and intestinal development of broilers to a certain extent. It is suggested that the stocking density of Cobb broilers can be increased to 20.3 birds/m² under the background of classical music stimulation.

Inulin is a fructosan type plant polysaccharide widely existing in nature, and it has many biological functions, such as promoting the absorbing of minerals, promoting glucose and lipid metabolism, anti-oxidation, prebiotic effect and so on. This article reviewed the extraction process and biological functions of inulin and its application in ruminant production, aiming to provide theoretical reference for the application of inulin in ruminants.

Tea seed meal is the residue of camellia oil. It has high contents of crude protein and carbohydrate, and contains unsaturated fatty acids, tea saponin, tannin, alkaloids, a small number of flavonoids, polysaccharides and other natural active ingredients. It has good nutritional value and functional properties. Due to different processing technology, tea seed meal can be made into powder, granule and cake. After soap extraction processing, the crude protein content of tea seed meal is increased, and the crude fiber content is decreased. It can be used as protein feed to replace part of soybean meal. In this paper, the nutritional value and functional properties of tea seed meal, the extraction process of active components and the application of tea seed meal in livestock and aquatic production were reviewed, in order to provide theoretical guidance for the development and utilization of unconventional feed.

This experiment was designed to investigate the effects of peppermint leaf powder on performance and egg nutritional composition of laying hens during late laying period.Two hundred and sixteen New Yang Black-feathered hens with similar egg production rate of (64.37±5.24)% in laying hens during the late laying period were randomly divided into four groups, hens in the control group fed a basal diet and the other three groups fed the basal diet supplemented with 0.1%, 0.2% and 0.4% peppermint leaf powder, respectively, with nine replicates in each group and six hens in each replicate. The whole test period was 35 days, including pilot trial for 7 days and formal trial for 28 days. The results showed as follows: 1) compared with the control group, supplementation of dietary peppermint leaf powder did not significantly increase the average daily feed intake (ADFI), feed/egg ratio, laying rate and average egg weight (P>0.05); meanwhile, contents of immunoglobulin G (IgG)and total protein (TP)in serum was significantly increased in the three treatment groups (P<0.05); dietary supplementation with 0.1% peppermint leaf powder significantly increased the number of large white follicles in the ovaries (P<0.05). 2) Compared with the control group, dietary supplementation of peppermint leaf powder significantly enhanced egg shell strength and improved egg shape index (P<0.05); there was also a tendency to increase in the contents of L-phenylalanine, L-tryptophan, L-isoleucine and total essential amino acids in egg white (0.05<P<0.10); 0.1% and 0.4% peppermint leaf powder had no significant effect on fatty acid contents in egg yolk (P>0.05). In conclusion, dietary 0.1% and 0.4% peppermint leaf powder can increase IgG and TP contents in serum of laying hens without affecting performance, which has the potential to enhance immunity of laying hens and improve egg quality.

This study was to investigate the effects of dietary bakery meal on reproductive performance of lactating sows and growth performance of weaning piglets, nursing piglets and growing-fattening pigs. In experiment 1, fifty healthy Landrace×Large White hybrid sows (1 week before farrowing) with similar body weight at 1 week before delivery were randomly divided into 2 groups with 25 replicates per group and 1 sow per replicate. The control group was fed a diet for lactating sows, and the experimental group was fed the diet which part of the corn and soybean oil in the diet of control group were replaced with 12% bakery meal, and the feeding experiment ended until the piglets were weaned. In experiment 2, a total of 351 Duroc×Landrace×Large White weaned piglets with similar body weight [(7.00±0.71) kg] were randomly divided into 3 groups with 9 replicates per group and 13 piglets per replicate. The control group was fed a diet for weaning piglets, and the experimental groups were fed the diets which part of the corn, soybean meal and soybean oil in the diet of control group were replaced with 10% and 20% bakery meal, respectively, and the feeding experiment lasted for 10 days. In experiment 3, a total of 72 Duroc×Landrace×Large White nursing piglets with similar body weight [(13.43±0.87) kg] were randomly divided into 3 groups with 4 replicates per group and 6 piglets per replicate. The control group was fed a diet for nursing piglets, and the experimental groups were fed the diets which part of the corn, soybean meal and soybean oil in the diet of control group were replaced with 6% and 12% bakery meal, respectively, and the feeding experiment lasted for 30 days. In experiment 4, a total of 252 Duroc×Landrace×Large White growing-fattening pigs with similar body weight [(32.60±0.78) kg] were randomly divided into 3 groups with 44 replicates per group and 21 piglets per replicate. The control group was fed a diet for growing-fattening pigs, and the experimental groups were fed the diets which part of the corn and soybean meal in the diet of control group were replaced with 6% and 12% bakery meal, respectively, and the feeding experiment lasted for 21 days. The results showed as follows: 1) compared with the control group, dietary added 12% bakery meal did not affect the reproductive performance of lactating sows (P>0.05). 2) Compared with the control group, dietary added 10% and 20% bakery meal significantly increased the average daily feed intake and average daily gain of weaning piglets (P<0.05), and significantly decreased the feed to gain ratio of weaning piglets (P<0.05). 3) Compared with the control group, dietary added 12% bakery meal significantly increased the average daily feed intake and average daily gain of nursing piglets (P<0.05), and significantly decreased the feed to gain ratio of nursing piglets (P<0.05). 4) Compared with the control group, dietary added 6% and 12% bakery meal significantly increased the average daily feed intake and average daily gain of growing-fattening pigs (P<0.05), and significantly decreased the feed to gain ratio of growing-fattening pigs (P<0.05). In conclusion, dietary added 12% bakery meal do not affect the reproductive performance of lactating sows, dietary added 10% and 20% bakery meal can improve the growth performance of weaning piglets, dietary added 12% bakery meal can improve the growth performance of nursing piglets, and dietary added 6% and 12% bakery meal can improve the growth performance of growing-fattening pigs.

This experiment was conducted to investigate the effects of guanidinoacetic acid on growth performance, slaughter performance, serum biochemical indexes, muscle fiber characteristics and gene expression of regulatory factors related to muscle development of finishing pigs. Forty-eight Duroc-Landrace-White crossbred pigs with similar body weight [(86.00±1.00) kg] were selected and randomly divided into three groups with four replicates in each group and four pigs in each replicate (half male and half female). The control group was fed a basal diet, the T1 group was fed the basal diet supplemented with 500 mg/kg guanidinoacetic acid, and the T2 group was fed the basal diet supplemented with 500 mg/kg guanidinoacetic acid+200 mg/kg betaine. The pre-feeding period was 3 days and the formal period was 38 days. The results showed as follows: 1) the final body weight, average daily gain and average daily feed intake of T1 and T2 groups were significantly higher than those of the control group (P<0.05); the feed to gain ratio of T1 and T2 groups was significantly lower than that of the control group (P<0.05), and the feed to gain ratio of T2 group was significantly lower than that of T1 group (P<0.05). 2) Compared with the control group, the carcass weight of T2 group tended to be increased (P=0.079). The dressing percentage and eye muscle area of T1 and T2 groups were significantly higher than those of the control group (P<0.05). 3) Compared with the control group, the serum low-density lipoprotein content on day 19 of T1 and T2 groups tended to be decreased (P=0.084). The serum urea content on day 38 of T1 and T2 groups was significantly lower than that of the control group (P<0.05); the serum total protein content on day 38 of T1 and T2 groups was significantly higher than that of the control group (P<0.05), and the serum total protein content on day 38 of T2 group was significantly lower than that of T1 group (P<0.05). 4) The muscle fiber cross-sectional area of T1 and T2 groups was significantly higher than that of the control group (P<0.05). 5) Compared with the control group, the gene relative expression level of myogenic factor 5 (Myf5) in muscle of T2 group tended to be increased (P=0.093). The gene relative expression level of myogenin (MyoG) in muscle of T2 group was significantly higher than that of the control group (P<0.05). In conclusion, the addition of guanidinoacetic acid and betaine in the diet can improve the growth performance, slaughter performance and muscle fiber cross-sectional area of finishing pigs, and promote the proliferation and differentiation of muscle fiber, and the combined addition of guanidinoacetic acid and betaine to promote growth is better than the addition of guanidinoacetic acid alone.

This experiment was conducted to investigate the effects of dietary stevia residue extract supplementation on growth performance, hematology and biochemical indexes, antioxidant activity, organ indexes, and visceral histopathology of weaned piglets, and to systematically evaluate the tolerance of weaned piglets to stevia residue extract. A total of 108 weaned piglets (Duroc×Landrace×Yorkshire) at 21 days of age with an average initial body weight of (6.79±0.02) kg were randomly divided into 3 groups with 6 replicates per group and 6 pigs per replicate. The control group was fed a basal diet, while the experimental groups were fed the basal diet supplemented with 400 or 4 000 mg/kg stevia residue extract, respectively. The trial lasted for 42 days. The results showed as follows: compared with the control group, 1) dietary stevia residues extract supplementation had no significant effects on average daily gain, average daily feed intake, ratio of feed to gain, and diarrhea rate of weaned piglets from days 1 to 28 and days 1 to 42 (P>0.05); 2) dietary stevia residues extract supplementation had no significant effects on hematology parameters of weaned piglets (P>0.05), but 4 000 mg/kg stevia residues extract supplementation significantly increased the serum alkaline phosphatase (ALP) activity (P<0.05); 3) 400 mg/kg stevia residue extract supplementation significantly decreased the serum malonaldehyde (MDA) content and increased the activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px) (P<0.05), and 4 000 mg/kg stevia residues extract supplementation significantly decreased the serum MDA content and increased the serum T-SOD activity (P<0.05); 4) dietary stevia residue extract supplementation had no significant effects on heart index, liver index, spleen index, lung index, kidney index and pancreas index (P>0.05), and no obvious pathological changes were discovered in the heart, liver, spleen, lung, kidney and other tissues. In conclusion, dietary supplemented with stevia residue extract can improve the antioxidant capacity of weaned piglets, but has no significant effects on growth performance, hematology parameters, or organ indexes, and no obvious pathological changes in tissues are discovered in weaned piglets. Therefore, weaned piglets can tolerate 4 000 mg/kg stevia residue extract.

Branched-chain amino acids (leucine, valine, isoleucine) have similar structure, same metabolic pathway and similar functions in human and animal bodies. Branched-chain amino acids have a variety of biological functions, such as leucine can stimulate protein synthesis and enhance immune function, valine and isoleucine can improve antioxidant performance, promote milk protein and milk fat synthesis. This paper summarized the physical properties, absorption and metabolism, and the biological mechanism of branched-chain amino acids and their application in pig and poultry production, in order to provide theoretical and practical reference for formulating functional and low protein diets for livestock and poultry using branched-chain amino acids.

Sunflower, known as the “pioneer crop of saline-alkali resistance”, is suitable for planting in Northeast, Northwest, North China and other saline-alkali areas. As one of the five oil crops in our country, the planting area of sunflower is stabilized at about 1 million hm². However, the huge volume of sunflower straw has not been effectively used. Sunflower straw contains rich nutrients and bioactive substances, which has a broad application prospect in the field of feed. The feeding value of its silage can reach 80% of that of corn silage. In this paper, the nutritional value and bioactive substances of sunflower straw were summarized by referring to the relevant literature published at home and abroad, and the influencing factors of sunflower silage were sorted out, in order to provide reference for production technicians and scientific researchers.

Stress diarrhea in weaned piglets can lead to weight loss, stunted growth and even death. This paper mainly reviewed the causes of stress diarrhea in weaned piglets and the main pathogenesis of stress diarrhea in weaned piglets from the aspects of intestinal barrier function, signaling pathway and endocrine. Finally, the nutritional regulation scheme for alleviating stress diarrhea of weaned piglets was summarized from the aspects of dietary nutrient level and feed additives, aiming at providing necessary reference for alleviating and treating stress diarrhea of weaned piglets.

Volatile organic compounds are important factors affecting the flavor of chicken, and their formation is closely related to the fatty acid composition of chicken and the lipid metabolism in chicken. This paper summarizes the main volatile organic compounds in chicken, including aldehydes, alcohols, alkanes, ketones, esters and heterocyclic compounds, and discusses the effects of fatty acid composition and lipid metabolism of diets on the volatile flavor of chicken to provide theoretical references for further improvement of chicken flavor through lipid regulation.

Cornell net carbohydrate and protein system (CNCPS) is a model proposed by scholars at Cornell University, to predict animal requirements and nutrient supply under different production situations by organically combining the biological properties of feeds with the digestive utilization of animals based on the information of animals, environment and feed ingredients. In recent years, more and more studies have been conducted to apply CNCPS for nutritional value assessment of feed ingredients. In this paper, the characteristics of CNCPS was briefly described, the nutritional value assessment of feed ingredients, the predictive assessment of ruminant diets and performance and its advancement were emphasized, and the application in combination with other evaluation systems was also analyzed.

When dairy cows are exposed to high temperatures indicative of heat stress, oxidative stress injuries and various inflammatory responses can easily occur. This often leads to a decrease in milk production and milk quality, resulting in significant economic losses. Selenium is an essential trace element for ruminants, involved in the regulation of antioxidation and anti-inflammatory functions within the body, and it possesses the ability to alleviate heat stress in dairy cows. This review discusses the harm of heat stress on dairy cows and the prevention control measures, the effects of selenium added to the diet, and its mitigation of heat stress. Moreover, the potential mechanisms by which selenium alleviates heat stress in dairy cows are summarized from the perspective of the triad interaction between oxidative stress, inflammatory responses, and immune function. This information is expected to provide a reference for the prevention and treatment of heat stress in dairy cows in production settings, as well as for the reasonable use of selenium products in animal production.