| This test regarded AA broilers as the test animals.studied the effect of β — mannanase adding into the basal diets at different levels and the sex factor on its productive performance.nutrients metabolism, carcass quality, intestinal microflora, pH value and immunity function.384 1-day-old AA broilers were divided from 192 female and 192 male broilers, male and female was assigned randomly into 4 groups with 4 replicate set with 12 broilers per replicate for a 42-day trail respectively. Group I was fed with basal diet without β —mannanase, Group II, III, IV were fed with basal diets adding 0.03%. 0.06% . 0.1% β — mannanase. The parameter of productive performance, nutrients metabolism, carcass quality, intestinal microflora, pH value and immune function were determined. The results were showed as follows:(1) The β —mannanase adding into basal diets at different levels can increase the productive performance, but the sex factor has no influence. Through the whole period(0~6w), compared with the control group, group II, III, IV daily weight gain (WG) increase by 4.10% (p>0.05) ,13.45%(p<0.05) and 11.71% (p<0.05);the daily feed intake (FI) increase by 3.21% (p>0.05) ,5.87% (p>0.05) and 7.24% (p>0.05);the feed/gain (F/G) decrease by 0.59% (p>0.05) ,6.51% (p<0.05)and 3.55% (p<0.05). And 0.06% 3 —mannanase can promot the broiler growth and improve the feedutilization more effective.(2) Compared with the control group, the apparent metabolic rate of DM and CP of group II, III, IV increased, and the nutrients metabolism of 0.06% adding level is higher, but the sex factor has no influence. In the early (0~3), it has no significance to increase the apparent metabolic rate of DM and CP;in the last (4~6), the apparent metabolic rate of DM of group II, III, IV increase by 1.34% (p>0.05), 4.35% (p<0.05) and 4.05% (p<0.05);the apparent metabolic rate of CP increase by 2.72% (p>0.05), 7.98% (p<0.05) and 7.19% (p<0.05).(3) The β —mannanase adding into basal diets at different levels can increase the carcass quality, but the sex factor has no influence. Compared with the control group, the slaughter ratio of group II, III, IV increase by 0.65% (p>0.05), 2.01% (p<0.05) and 1.35% (p<0.05);the half thorax ratio increased by 0.53% (p>0.05), 3.96% (p< 0.05) and 3.30% (p<0.05);the whole thorax ratio increased by 1.29% (p>0.05), 5.29% (p<0.05) and 3.46% (p<0.05);abdomen fat rate decrease by1.95% (p>0.05), 4.88% (pS>0.05) and 3.41% (p>0.05).(4) The P — mannanase adding into basal diets at different levels can increase the number of the lactic acid bacillus and bifidobacteria, reduce the number of Eschenchia coli and pH values, protect the health of the intestinal environment, but the sex factor has no influence. Compared with the control group, the number of Escherichia coli of II, III, IV group decreased by 2.82% (p<0.01), 5.21% (p<0.01) and 6.63% (p<0.01);Lactic acid bacillus increased by 1.02% (p<0.05), 1.09% (p<0.05) and 1.78% (p<0.05);bifidobacteria increased by 1.42% (p<0.01), 2.37% (p<0.01) and 3.10% (p<0.01);pH values reduced by 0.59% (p<0.05),1.04% (p<0.01) and 1.34% (p<0.01).(5) The 3 —mannanase adding into basal diets at different levels has no remarkably influence to the immunity organ index, and the sex factor has no influence to the immunity organ index. Compared with the control group, II, III, IV group's spleen index increased by 3.41% (p>0.05), 6.34% (p>0.05) and 7.32% (p>0.05);bursal index increased by 5.38% (p>0.05), 8.46% (p>0.05) and 7.03% (p>0.05);thymus index increased by 5.21% (p>0.05), 8.06% (p>0.05) and 7.11% (p>0.05).(6) The 3 —mannanase adding into basal diets at different levels can enhance the serum IgA, IgG content, but the sex factor has no influence. Compared with the control group, II, III, IV group's IgA content increased by 17.14% (p<0.05), 51.43% (p<0.01) and 34.28% (p<0.01);IgG content increased by 23.96% (p<0.05), 36.28% (p<0.01) and 28.99% (p<0.01), but has no significant effects on serum IgM concent. Considering all the above, the serum IgA, IgG content with 0.06% 3 — mannanase are the best. |
PDF Full Text Request