| D-LysAsnProTyr is an immune small peptide. This trial is to study the mechanism of the D-LysAsnPro on performance and immunity of broilers in order to provide the proof for practical using. The trial has adopted one-factor completely random design. 7-day-old 300 Avian chicks were divided into 5 treatments, randomly, and 3 replicates per treatment and 20 birds each replicate, hens and cocks are equal, respectively. The trial lasted 49 days. Each chick was treated with 50μl mixture of D-LysAsnProTyr (the levels are 0μg,15μg,20μg,25μg,30μg per chick ) and the ND Ⅳvaccine via nose and without antibiotic providing. Feed and water were given ad libitum. Weight gain, feed intake and feed/gain were calculated. ND antibody level and ANAE~+ of lymphocyte were measured. The immune organs exponent and the whole energy, protein concentration and their retention were determined through slaughter without blood lose when the trial ended.The main results were as follows:1. D-LysAsnProTyr influenced broiler immune state and changed broiler performance, but didn't affect its feed intake. The result had relationship with D-LysAsnProTyr concentration. 20μg and 25μg enhanced the broiler spleen weight, humoral, cellular immunity and growth (P<0.05) . The effect of D-LysAsnProTyr on birds' related to its immune trait.2. D-LysAsnProTyr concentration showed quadratic curves with broiler daily weight gain, final body weight, HI antibody levels, ANAE~+ percentage, the optimal concentrations were 22.19, 22.22, 23.05, 22.10μg per chicks respectively.3. The average HI antibody level in trial had the strong correlation with daily weight gain ( r=0.8745,p=0.0524 ) , feed efficiency(r=-0.8747,p=0.0522) and finalweight(r=0.8744,p=0.0524).The ANAE+ of lymphocyte had strong correlation with daily weight gain (r=0.8779,p=0.0503), feed efficiency (r=-0.8747,p=0.0712) and final weight (r=0.8744,p=0.0959) . |
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