Sheep gastrointestinal development in response to different dietary treatments

Physical maturation of the ruminal epithelium has previously been linked to ruminal production of VFA following the initiation of solid feed intake. This study was conducted to evaluate the effect of VFA administration and energy intake on sheep gastrointestinal development. Twelve lambs were removed from their dams at birth and trained to nurse on nipple buckets. All lambs consumed milk until 49 d of age and were subsequently assigned to one of four treatments: continued ad libitum intake of milk (M), ad libitum intake of a pelleted lamb starter (F), restricted intake of a pelleted lamb starter (P: paired to the energy intake of M lambs), or continued ad libitum intake of milk replacer plus an oral VFA solution (V; 55.2:36.9:7.2 mmol/100 mmol acetate:propionate:butyrate) via stomach tube to provide 10% of the predicted NEg. At slaughter visceral organs were removed and separated. Ruminal and intestinal tissues were weighed and intestinal tissue length was determined. Subsections of the rumen, duodenum, jejunum, ileum, and the colon were used to determine total, epithelial and musculature DM, protein, DNA, and RNA. Data are presented as a percent of empty body weight (%EBW) unless otherwise noted. Both F and P stimulated increases (P<0.05) in rumen mass (2.232 0.077 and 2.126 0.238 %EBW, respectively), while V treatment did not (0.761 0.038 %EBW) in comparison to milk fed animals (0.88 0.104 %EBW). Small intestinal weights (%EBW) were unaffected by P and F relative to milk fed animals yet increased in V (3.32 0.982, 2.66 0.242, 3.122 0.354, and 4.061 0.158 %EBW for M, P, F, and V, respectively). The ratio of small intestinal length to empty body weight declined (P<0.05) with intake of solid feed and VFA treatment. However, wet weight per unit length of the small intestine was increased by F, P and V above that observed for M. Thus, although VFA treatment at this dose was insuf®cient to induce normal ruminal development, intestinal physical development was stimulated by oral VFA infusion in developing lambs. # 2000 Elsevier Science B.V. All rights reserved.