Effects of different ratios of neutral detergent fiber to starch in starters on the development of digestive tract of lambs

In this study, we investigated the effects of neutral detergent fiber (NDF) to starch ratios on the development of the digestive tract of lambs. Sixty male Hu lambs with similar birth weights (3.14 ± 0.05) kg were randomly divided into three groups with 20 lambs in each group. At 10 days of age, the lambs were supplemented with NDF to starch ratios of 0.50 (group Ⅰ), 0.70 (group Ⅱ) and 1.00 (group Ⅲ). They were weaned at 35 days of age and slaughtered at 56 days of age. Following results were obtained: 1) The height of the rumen papilla, the height and width of the primary crease of the reticulum, and the thickness of the muscular layer in group Ⅱ were significantly higher than those in groups Ⅰ and Ⅲ (P < 0.05), while the height of the rumen papilla in group Ⅲ was significantly higher than that in group Ⅰ (P < 0.01). 2) The crypt depth of the duodenum and ileum in group Ⅱ was significantly lower whereas the thickness of the muscular layer was significantly higher than that observed in groups Ⅰ and Ⅲ (P < 0.05). The crypt depth of the duodenum in group Ⅲ was significantly lower than that in group Ⅰ (P < 0.01). In conclusion, starting diets with an NDF to starch ratio of 0.70 is beneficial for the digestive tract development of lambs. The results of this study can provide a reference for the preparation of starter diets for lambs.