Study on nutritional quality of cotton stalks fermented with brown sugar and its effects on apparent nutrient digestibility of Hu sheep

GAO Li; ZHANG Junyu; BA Yinbate; ZENG Tao; AYIJIANG Kakeerman; MIRIZATI Aireti; YANG Hu

doi:10.13557/j.cnki.issn1002-2813.2025.20.002

Abstract：The experiment aimed to investigate the nutritional quality of cotton stalks fermented with different levels of brown sugar and the effect of cotton stalks micro-storage on the apparent nutrient digestibility of Hu sheep.A single-factor experimental design was adopted.0(group CK),0.5％(group A),1.0％(group B),1.5％(group C),and 2.0％(group D)of brown sugar were added to the expanded cotton stalks for 56 days of micro-storage.Each treatment had four replicates.Thirty healthy Hu sheep with similar body weight and age were selected and randomly divided into five groups,with six replicates in each group,and one sheep in each replicate.The control group(group XCK)was fed the basal diet,while the experimental groups were fed with 10％(group XA),20％(group XB),30％(XC group)and 40％(group XD)of cotton stalks micro-storage(with 1％brown sugar added)as a substitute for the basal diet,respectively.The pre-test period was seven days,and the formal test period was six days.The results showed that during different fermentation periods(except for fermentation day 0),the pH value of each experimental group was significantly or extremely lower than those of the CK group(P＜0.05 or P＜0.01).At 7 days of fermentation,the pH value of group A was extremely higher than those of groups B,C,and D(P＜0.01).Compared with group CK,the total acid and lactic acid(LA)concentrations in group D were extremely increased by 13.81％and 24.87％(P＜0.01),while the acetic acid(AA)and butyric acid(BA)concentrations were extremely decreased by 10.48％and 65.67％(P＜0.01).Compared with group CK,the neutral detergent fiber(NDF)and acid detergent fiber(ADF)concentrations in group D of the micro-storage of cotton stalks were extremely reduced by 8.70％and 13.90％(P＜0.01).The free gossypol(FG)content in group D was the lowest,and it was 16.51％lower than that of the group CK(P＜0.01).The apparent digestibility of dry matter(DM),organic matter(OM),crude protein(CP),NDF,and ADF by the Hu sheep in group XB was the highest.The study shows that adding 1.0％brown sugar can improve the quality of cotton stalks micro-storage,reduce the FG content,and when the cotton stalks micro-storage replaced 20％of the basal diet,the apparent nutrient digestibility of the diet by the Hu sheep is higher.