Effects of rice straw addition to diet on Hu sheep production and slaughter performance, biochemical blood indices, and meat quality

The aim in this study was to investigate the effects of different rice straw treatments on the production performance, biochemical blood indices, slaughter performance, and meat quality of Hu sheep. Eighty healthy Hu sheep, approximately 85 day old and 23.53 kg, were selected for this study. These 80 sheep were randomly divided into four groups of 20 sheep each, one control and three experimental groups, with prefeeding and normal feeding periods of 7 and 66 days, respectively. The control group received a diet supplemented with dry rice straw, and the experimental groups received diets supplemented with ammoniated, fermented, or compound-bacteria-fermented rice straw. The average daily weight gain and dry matter feed intake in the three experimental groups were significantly higher than those in the control group (P < 0.01). The feed-to-weight-gain ratio of the compound-bacteria-fermented rice straw group was significantly lower than that of the control and fermented rice straw groups (P < 0.05). The serum glucose and total cholesterol levels were significantly higher in the three experimental groups than in the control group (P < 0.01). The live sheep in the compound-bacteria-fermented rice straw group were significantly heavier prior to slaughter than the sheep in the control and ammoniated rice straw groups (P < 0.05). The carcasses of the sheep in the fermented and compound-bacteria-fermented rice straw groups were significantly heavier than those in the other two groups (P < 0.01). The dressing percentage of the ammoniated rice straw group was significantly lower than those of the three other groups (P < 0.05). The eye muscle area of the sheep in the fermented rice straw group was significantly larger than that of the sheep in the control, ammoniated rice straw, and compound bacteria-fermented rice straw groups (P < 0.01). The water loss rate of the meat from the sheep in the fermented rice straw group was significantly smaller than that of the meat from the three other groups (P < 0.05). The yellowness of the sheep meat from the three experimental groups was significantly lower than that of the control group (P < 0.01). In summary, the addition of ammoniated, fermented, and compound-bacteria-fermented rice straw to the diet of Hu sheep improves production performance. The addition of compound-bacteria-fermented rice straw most strongly improved the production performance and meat quality of Hu sheep.