| The paper studied the effects of different levels of dietary L-carnitine on performance of growth, semen quality, reproductive performance, some physiological and biochemical indices in serum and seminal plasma of cocks. Linear regression analysis was carried on to explore the requirments of L-carnitine of Nan-dan-yao cock during reproductive period. Experiment one: The study adopted one-factor completely random distract design. According to1factors6horizontal methods designs experiment.24Guangxi Nan-dan-yao breeder roosters at37-week-old were selected and randomly divided into6groups of4roosters each, with1rooster per replicate. The diets for roosters were supplemented with0,125,250,375,500,750mg/kg L-carnitine respectively. Another480hens, healthy and the same old, were also randomly alloted to6groups of80birds each, corresponding to the experiment roosters. The tests lasted from June4,2011until October8,2011, which was a period of18weeks and the results are as follows. The results indicated that the dietary supplement level of L-carnitine had significant effects on the semen volume(p<0.01), the sperm vitality (p<0.01), sperm density (p<0.01), and the number of effective sperm (p<0.01), and indicates that there was no significant effect on the average body weight of the chickens(p>0.05), full body weight increase, the pH of semen(p<0.05); had significant effects on the fertilization rate(p<0.01), hatching rate of fertilized eggs (p<0.05), the rate of healthy chickens (p<0.05); indicated a significant increase on the contents of T (p<0.01) in serum, the AKP activities in serum (p<0.05), significant decrease serum TC (p<0.01), as shown by a significant difference of; but indicated no significant difference on LDH, BUN in serum (p>0.05); and (p<0.05) indicated a significant decrease on the TC in semen, but indicated no significant difference on AKB and LDH.The full body weight increase (p<0.05), the sperm vitality(p<0.01), sperm density(p<0.01), the number of effective sperm (p<0.01), the concentration of T and the AKP activities in serum (p<0.01) were significantly correlated with the level of dietary L-carnitine. The L-carnitine level of diet significantly correlated with the qualified kind egg rate, the fertilization rate, hatching rate of fertilized eggs. The L-carnitine level of diet significantly negative correlated with the TC in serum(p<0.01), the BUN in serum(p<0.05), the TC in semen(p<0.01). The L-carnitine level of diet at the inflexion of the fertilization rate of eggs and the sperm vitality was separately375mg/kg and500mg/kg, which can be adopted as the range level of dietary L-carnitine.Experiment two:This research studied the effect of different levels of L-carnitine on egg production performance, reproductive performance, egg quality and some physiological and biochemical indices in serum of hens in Nan-dan-yao chicken. In addition it also looked at the effect of serum biochemical parameters and egg yolk cholesterol content. The study adopted one-factor completely random distract design. L-carnitine added with4treatments were Omg/kg,25mg/kg,50mg/kg,100mg/kg. A total of864Nan-dan-yao laying hens at37weeks old were randomly divided into4groups of216,4duplications each. The tests lasted from June4,2011until October8,2011, which was a period of18weeks and the results are as follows. The results indicated that the dietary supplement level of L-carnitine had significant effects on the egg laying rate, fertilization rate, and hatching rate of fertilized eggs (p<0.05), and indicates that there was no significant effect on the average body weight of the chickens(p>0.05), full body weight increase(p>0.05), qualified kind egg rate(p>0.05), indicates a significant increase in the number of healthy chicks, but had no significant difference (p>0.05); had a significant different of (p<0.05) on Haugh unit, while (p>0.05) indicated no significant difference on the average egg weight, egg shape index, eggshell thickness, eggshell strength, yolk yellow, egg yolk percentage and protein percentage; a significant difference of (p<0.05) indicated a significant increase on serum GSH-Px and serum AKP activity; significant decrease serum TC (p<0.01), TG(p<0.05), HDCL(p<0.05) as shown by a significant difference of; but indicated no significant difference in serum TP, ALB, GLO, BUN, GLU, ALT, GOT (p>0.05); and indicated a significant difference on the egg yolk cholesterol(p<0.05). From reproductive performance and egg quality to consider, adding amount of50mg/kg most appropriate. |
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