Effect of enzyme preparation supplements in diets with different straw sources on the performance and ruminal fermentation of Hu sheep

The objective of this study was to investigate the effects of enzyme preparations added to corn (Zea mays) stover and wheat (Triticum aestivum) stalk dietary sources on the performance, ruminal fermentation parameters, serum biochemical indicators, and nutrient digestibility in Hu sheep. A 2 × 2 factorial arrangement was used for this experiment. Fifty-two healthy Hu sheep male lambs were selected and randomly divided into four treatments with 13 sheep in each treatment. The four treatments were corn stover with zero (group Ⅰ) and 0.3% (group Ⅱ) enzyme preparation supplement, and wheat straw with zero (group Ⅲ) and 0.3% (group Ⅳ) enzyme preparation supplement. The trial period included 7 d for the preliminary test period and 63 d for the formal trial period. The results showed that: 1) There was a significant increase in average daily gain (ADG) and dry matter intake (DMI) of Hu sheep, and the feed to gain (F/G) was significantly decreased (P < 0.05). 2) The dry matter digestibility (DMD) and organic matter digestibility (OMD) in added enzyme preparation groups of Hu sheep significantly improved (P < 0.05). There was no significant effect on the digestibility of other nutrients, nor was there a significant difference between straw sources and enzyme preparations in the nitrogen metabolism (P > 0.05). 3) Neither the straw source nor the enzyme preparations affected the concentrations of alanine aminotransferase (ALT), cholesterol (CHO), alkaline phosphatase (ALP), urea nitrogen (UN), aspartate aminotransferase (AST), total triglycerides (TG) and lactate dehydrogenase (LDH) in the blood of Hu sheep (P > 0.05), but the enzyme preparation supplements significantly increased the concentration of glucose (GLU) (P < 0.05). 4) Enzyme preparation supplements significantly increased the total volatile fatty acid (TVFA) concentration in rumen fluid (P < 0.05), but had no significant effect on the proportion of individual fatty acids and acetate to propionate (A:P) ratio (P > 0.05). In summary, the enzyme preparations in diets with different straw sources significantly promoted rumen fermentation, effectively improving the digestion and utilization of fibrous substances and the performance of fattening Hu sheep.