Effects of Dietary Protein and Fat Levels on Growth Performance and Serum Biochemical Parameters of Male Mink

This experiment was conducted to evaluate the effects of dietary protein and fat levels on growth performance and serum biochemical parameters of male minks during the growing period. A total, of 90 healthy male minks at the age of 60 d were randomly assigned into six groups with 15 replicates per group and one mink per replicate. The minks were fed six experimental diets with two protein levels （32% and 36% ） and three fat levels （ 10% , 20% and 30% ） for a 7-day preliminary period and then for 60-day experimental period. The results showed that the final body weight and average daily weight gain （ADWG） were significantly higher in low-protein, middle-fat group and low-protein, high-fat group than those in low-protein, low-fat group and high-protein, low-fat group （P 〈 0. O1 ）. The final weight and ADWG were increased with dietary fat level increasing, and the two indices of 20% and 30% fat groups were significantly higher than those of 10% fat groups （ P 〈 0. O1 ）. The ratio of feed intake to weight gain （F/G） in low-protein, high-fat group was the lowest, which was significantly lower than that in low- protein, low-fat group and high-protein, high-fat group （P 〈 0.05 ）. Serum urea nitrogen （UN） in low-protein, high-fat group was significantly lower than that in other groups （P 〈 0. 01 ）. Serum alanine transaminase （ALT） activity in 32% protein groups was significantly higher than that in 36% protein groups （P 〈 O. 05）. Serum triglyceride （TG） content in low-protein, high-fat group and high-protein, high-fat group was significantly higher than that in low-protein, low-fat group and high-protein, low-fat groups （P 〈 0.05 ）. Serum TG, total cholesterol （TCHO） and high-density lipoprotein （HDL） contents increased with the increase in dietary fat level, and they were all the highest in low-protein, high-fat group. The growth performance and serum biochemical parameters of minks were not affected by the interaction between dietary protein and fat levels （P 〉 O. 05 ）. Considering all the factors, when the dietary protein is 32% and the fat level is 20% to 30% under the condition of this experiment, the dietary protein and fat utilization rates are higher, and the male minks during the growing period can get a better growth performance.

Effects of Compound Acidifier on Growth Performance and Serum Biochemical Parameters of Heat-stressed Wenchang Chickens

[Objective]The paper was to investigate the effects of compound acidifier on growth performance and serum biochemical parameters of heat-stressed Wenchang chickens.[Method]A total of 28881-day-old Wenchang chickens with the same genetic background and similar initial weight(985.63±20.35 g)were randomly divided into four groups,four replicates per group and 18 chickens per replicate.Birds were fed the basal diet supplemented with 0 g/kg(control group),1 g/kg(groupⅠ),2 g/kg(groupⅡ)and 3 g/kg(groupⅢ)compound acidifier.The trial lasted 35 d.[Result]The daily gain of experimental groupⅠwas significantly higher than those of control group and groupⅢ(P<0.05),and the feed intake of experimental groupⅠwas also markedly higher than that of control group(P<0.05),but the feed gain ratio of experimental groupⅠwas significantly lower than that of groupⅢ(P<0.05).Compared with control group,the serum total protein and albumin levels of experimental groupⅠincreased(P>0.05),but the serum uric acid concentration decreased(P>0.05).[Conclusion]Supplementing 1 g/kg compound acidifier could improve the growth performance of heat-stressed Wenchang chickens.

Effects of Dietary Betaine on Production Perform-ance,Egg Quality and Serum Biochemical Indexes of Layers under Heat Stress Condition

[ Objective ] This experiment was conducted to study the effects of dietary betaine on peiformance, egg quality and serum biochemical parameters of lay- ing hens under heat stress condition. [ Method] A total of 600 22-week-old commercial Roman laying hens were randomly divided into five groups, with eight repli- cates in each group and 15 hens in each replicate. Group I was taken as the positive control group, and laying hens in group ] were fed with basal diets in anrmal thermal environment. Temperature humidity index of group 1 was between 64.9 and 68.9. Group II was taken as the negative control group, and laying hens in group II were fed with basal diets under heal stress condition. Temperature humidity index of group II was higher than 72. laying hens in groups llI-V were fed with basal diets supplemented with 200,400 and 600 mg/kg betaine under heat stress condition respectively, and temperature humidity indexes in groups III-V were all higher than 72. The experiment lasted for 14 weeks. [ Results ] Results showed that there were no significant differences in average daily feed intake, feed egg ratio and broken egg rate among different test groups （P 〉 0.05 ）. Hen-housed laying rate, hen-housed egg yield, serum total protein （TP） content and serum alkaline phosphatase （AKP） activity in group II were significantly lower than those in group I（ P 〈0.05 ）. However, activities of glutamic-oxalacetic transaminase （GOT）, creatine kinase （CK） and glutamic-pyruvic transaminase （GPT） in group II were significantly higher than those in group i （P 〈0.05 ）. Hen-housed laying rate, hen-housed egg yield and serum TP content in group IV were significantly higher than those in group II（ P 〈 0.05 ）. Hen-housed egg yield, serum TP eontent and serum albumin （ALB） content in group V were significantly higher than those in group II（P 〈0.05）. Activities of serum CK and Girl in groups IV and V were significantly lower than those in group II （ P 〈 0.05 ）, serum triglyceride （TG） content in group V was significantly lower than that in group 11 （ P 〈 0.05 ）. [ Conclusion] Metabolism and physiological function of laying hens could be affected by heat stress, and which caused a decline in performance. Adding of dietary betaine in diets could improve hen-housed egg production and hen-housed laying rate, which could also improve the health of laying hens under heat stress condi- tion. The appropriate dietary adding content of betaine was 400 mg/kg.

Effects of early energy and protein restriction on growth performance, clinical blood parameters, carcass yield, and tibia parameters of broilers

financially supported by the Science and Technology Develop Project of Northern Jiangsu, China （BN2015136）;the Priority Academic Program Development of Jiangsu Higher Education Institution, China

Effects of protein sources for milk replacers on growth performance and serum biochemical indexes of suckling calves

This study investigated the effects of protein sources for milk replacers on growth performance and serum biochemical indexes of suckling calves. Fifty Chinese Holstein bull calves with similar BW and age were randomly allocated to 5 groups(1 control and 4 treatments) of 10 calves in each group. Five types of milk replacers were designed to have the same level of energy and protein. The protein source for milk replacers of the control group was full milk protein(MP). The protein source of milk replacers of the 4 treatment groups was composed of MP and one vegetable protein(VP)(30 and 70% of total protein). The4 types of VP were soybean protein concentrate(SP), hydrolyzed wheat protein(WP), peanut protein concentrate(PP), and rice protein isolate(RP). Results of the experiment showed: 1) there was no significant difference on average daily gain(ADG) and feed:gain ratio(F:G) among the MP, SP and RP groups(P > 0.05), whereas the ADG and F:G of the WP and PP groups were significantly lower compared with the MP group(P < 0.05); 2) there was not a significant difference in withers height, body length and heart girth among treatment groups compared with the MP group(P > 0.05). Thereby the 4 VP milk replacers had no adverse effects on body size of calves; 3) all groups showed no significant difference in the serum contents of urea nitrogen, total protein, albumin, globulin, β-hydroxybutyrate, growth hormone, insulin-like growth factor-1, and the ratio of albumin to globulin(A:G)(P> 0.05). In conclusion, SP or RP(accounts for 70% of the total protein) as calf milk replacers could substitute MP, whereas wheat gluten and PP had a significant adverse effect on growth performance in this experiment.