Effect Of Environmental Temperature And Vitamin A On Perforemance And Biochemical Indexes Of Drake Rearing In Cage

This experiment studied the effects of environmental temperatures and dietary vitamin A levels on performance and biochemical indexes of drake (12~17 weeks) rearing in cage. A 2×3 factorial arrangement of treatments were employed with two temperature levels (18±1,2±1℃) and three vitamin A levels (4000,10000,15000IU/kg) . So there were six trials as follows: group I, group II, group III, group IV, group V, and group VI, respectively. A total of 144 drakes (JIN Ding duck,12 weeks old) were randomly allotted into six trials. Thus, each trial contained six replicates with four drakes. There were no significant differences in those drakes'weight.The results of feeding experiment showed as follows:Environmental temperature significantly affected average daily gains(ADG),average daily feed intake (ADFI) and feed/gain (F/G) (P<0.01). The final body weight,ADG and F/G were significantly affected by vitamin A levels (P<0.01). There was significant (P<0.01) effect on ADG of interaction between environmental temperatures and vitamin A levels.The results of slaughter experiment showed as follows:1. Environmental temperature significantly affected bursa index,thymus index and spleen index(P<0.01). Bursa index was significantly altered by vitamin A levels (P<0.01). However, thymus index and spleen index were not changed. There was significant (P<0.01) effect on spleen index of interaction between environmental temperatures and vitamin A levels.2. Testicular relative weight and testicular relative length were significantly(P<0.01) influenced by environmental temperatures. However , vitamin A levels did not influence testicular relative weight or testicular relative length. There were no significant effects on testicular relative weight or testicular relative length of interaction between environmental temperature and vitamin A levels.The results of analytical experiment showed as follows:1. Environmental temperature significantly affected Total antioxidant capacity (T-AOC),Glutathione peroxidase (GSH-PX),Catalase (CAT) and Superoxide Dismutase (SOD) (P<0.01), but had no significant influence on Malondialdehyde (MDA). T-AOC and CAT were significantly altered by vitamin A levels (P<0.05). However, GSH-PX,SOD and MDA were not affected. There were significant effects on T-AOC (P<0.01),GSH-PX (P<0.01),SOD (P<0.05) and MDA (P<0.05) of interaction between environmental temperature and vitamin A levels.2. Triiodothyronine (T3),thyroxin (T4) and growth hormone (GH) levels were significantly(P <0.01) influenced by environmental temperatures. However, insulin (Ins) and insulin-like growth factor-I (IGF-I) were not influenced. The concentrations of T4,GH and IGF-I were significantly altered by vitamin A levels (P<0.01), but the concentrations of T4 and Ins were not influenced. There were not significant effects on T3,T4 and IGF-I of interaction between environmental temperatures and vitamin A levels. However, there were significant effects on GH(P<0.01) and Ins(P<0.05).3. FSH(P<0.05), LH and T (P<0.01) were significantly influenced by environmental temperatures. There was no indications that vitamin A levels significantly influenced T level, but the levels of LH (P<0.05) and FSH (P<0.05) appeard to be significantly influenced by vitamin A levels.There was significant effect on LH of interaction between environmental temperature and vitamin A levels (P<0.05). However, there were not significant effects on FSH and T levels.