The experiment was conducted to study the effects of riboflavin supplementation on hormonal secretion of laying ducks at low ambient temperatures. Two factors (temperature×riboflavin) interactive experimental design was used in the experiment. The ambient temperatures were (2±1) ℃ and （18±1） ℃, and supplemental levels of riboflavin in the diet were 4,16 and 32 mg/kg, respectively. A total of 144 laying ducks (Jinding duck, female, 12 weeks old) were randomly allotted to 6 treatments with 6 replicates per treatment and each replicate comprised 4 ducks. The experiment lasted for 42 days. The results showed that low ambient temperatures had no significant effects on the final body weight and average daily gain (ADG), and the contents of thyroxin (T4), insulin (Ins), insulin growth factor-Ⅰ (IGF-Ⅰ), luteinizing hormone (LH), progesterone (P4) and cortical hormone (Cort) in serum of laying ducks (P>0.05), but significantly affected the ratio of feed to gain (F/G, P<0.05) and average daily feed intake (ADFI, P<0.01), and the contents of triiodothyronine (T3, P<0.01), growth hormone (GH, P<0.01), follicle-stimulating hormone (FSH, P<0.01) and estradiol（E2, P<0.01) in serum of laying ducks. There was no interaction on final body weight and ADG, and the contents of T4, E2 and P4 in serum of laying ducks between ambient temperature and riboflavin (P>0.05), whereas there was an interaction on F/G (P<0.05) and ADFI (P<0.01), and the contents of T3 (P<0.05), GH (P<0.01), Ins (P<0.01), IGF-Ⅰ (P<0.01), FSH (P<0.01), LH (P<0.01) and Cort (P<0.01) in serum of laying ducks. In conclusion, low ambient temperatures affect the secretion of T3, GH, FSH and E2, but do not affect the contents of Ins, T4, P4 and Cort in serum, and there is an interaction between temperature and riboflavin on F/G, ADFI, the contents of T3, GH, IGF-Ⅰ, FSH and LH.［Chinese Journal of Animal Nutrition, 2011, 23（6）：943 -949］
LU Yan,REN Yanming,WANG An
. Effects of Riboflavin Supplementation on Hormonal Secretion of Laying Ducks at Low Ambient Temperatures[J]. Chinese Journal of Animal Nutrition, 2011
, 23(06)
: 943
-949
.
DOI: 10.3969/j.issn.1006-267x.2011.06.009
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