Studies On The Effects Of Probiotics On Performance And Meat Quality Of San Huang Chickens

This trail consisted of two stages.The effects of probiotics on performance and health of San Huang chickens were studied in the first stage.1560 day-old chickens were allotted freely to two treatments with two replicates of 780 chickens each.The treatment encompassed :1) 0% probiotics in the basic diet as control and 2) 0.1% probiotics in the diet. The probiotics used in the experiment consists of 1 Lactobacillus and 3 Bacilluses and they were also the same in the second stage. The experiment diets were fed for 6 weeks. Feed intake, average body weight, diarrhea rate were recorded weekly. At 49 days of age, intestinal floras content was measured. The results showed that the body weight gain of birds fed 0.1% probiotics diet was higher than that of the control by 4.6%, 7.21% (p<0.01) and 7.09%(p<0.05) in the first week, the third week and the fifth week, respectively. However,the weight gain of chicks gived 0.1% probiotics diet was lower than that of the control by 4.06%(p<0.05) in the sixth week. No significant difference was observed in other weeks(p>0.05). The feed conversion rate of chickens fed 0.1% probiotics diet was higher than that of the control by 15.11% (p<0.01) and 16.12% (p<0.05) in the first week and in the third week, respectively.There were nosignificant difference in other weeks(p>0.05).The average body weight gain of birds gived 0.1% probiotics diet was higher than that of the control by 12.64%(p<0.01), and feed conversion rate was lower than that of the control by 9.23%(p<0.05) from 0 to 6 weeks of age. Both contents of Escherichia coli in jejunum and caecum of probiotics treatment were lower by 27.61%and 25.57%(p<0.05) than those of the control, respectively. The increased content of Lactic acidin entric was found in the probiotics group (p>0.05). Both the diarrbea rate and the mortality of the probiotics group declined when compared with those of the control (p>0.05).The effects of stocking density and probiotics on performance, health and meat quality of San Huang chickens were studied in the second stage. A 3X2 factorial arrangment of treatments was used (3 level stocking density were A: 5 birds per square metre, B: 10 birds per square metre, C: 13 birds per square metre; 2 level probiotics were 1:0, II: 0.1%). 1120 49-day-old chickens were allotted randomly to six treatments with two replicates each. The experiment diets were fed for 11 weeks. Feed intake, average body weight, diarrhea rate were recorded two weeks once. At 18 weeks of age the slaughter performances and meat quality were determined.The results suggested that during the period of 9 to 18 weeks the effects on body weight gain were subject to stocking density X probiotics interactions (p<0.01). The body weight gain of BII group was higher than that of BI,AII and CII groups by 3.56%(p<0.05) , 4.68% and 5.19% (p<0.01), respectively. No significant difference was found in other groups (p>0.05). Stocking density was the main factor affected on the feed conversion rate. Feed conversion rate of BII and CI groups were lower than that of A, group by 3.68% and 4.03% (p<0.05), respectively. BII and CII groups were lower than that of AII group by 5.38% and 5.55% (p<0.05), respectively.There were no significant difference in other groups (p>0.05). No diarrhea rate of all probiotics groups were observed. However there were 0.36% inthose probiotics free groups, but no significant difference was found between them (p>0.05). The effects of stocking density and probiotics on slaughter performance and meat quality were generally small (p>0.05). However probiotics tended to depress the contents of crude protein , fat and the unsaturated fatty acid not only in the breast but also in the thigh muscle. The distance between the fibre bundles and the fibre density decreased too, though the opposite effect was observed for the content of the saturated fatty acid in the muscle. The meat quality tended to become worse with increasing the performance according to the results of the composite evaluation of the meat quality.