Effect Of Early Weaning On Performance And Gastrointestinal Tract Development Of Hu Lambs

Forty-eight new born Hu lambs with born weight of (3.51±0.57 kg) were randomly evenly divided into two groups in order to study the effect of early weaning on performance and gastrointestinal tract development of Hu lambs. Lambs in early-weaned group and control group were fed starter from 7 d of age and weaned at 28 d and 56 d separately. Growing diet gradually introduced since 3 d after weaning of control group in both groups. Lambs in both groups were slaughtered and sampled on 42,56,70,84 d for measuring of weight, volume of compartments of gastrointestinal tract, and length of intestinal tract. Small intestinal tissues and mucosa were sampled for the measuring of morphology indicates and relative expression of transporter genes. The results showed as follows:1. Early-weaning had no influence on performance of Hu lambs at 84 d in this experiment (P >0.05)2. The weight and volume of reticulorumen, omasum and relative weight (% of live weight、% of gastrointestinal tract weight, and% of stomach weight) and relative volume (% of stomach volume) of reticulorumen in early-weaned group were significantly higher than those in control group (P<0.05). There were no significant differences in weight and length of all compartments of intestinal tract between two groups at all time points (P>0.05) except the weight of colon at 70 d.3. ACTB was the best reference gene of relative q-PCR for Hu lamb small intestinal mucosal, and PGK1 following closely.18S rRNA and GAPDH were out of choice for its worst stability performance.4. Early weaning improved muscular layer thickness significantly(P<0.05). Small intestinal tract adapted solid feed more efficiently in early weaned group for the absorb ability and maturity of duodenum, jejunum, ileum were higher.5. Lambs weaned at 28 d improved relative expression of SGLT1 in duodenum mucosa and FATP4 in jejunum mucosa. But relative expression of SGLTl in early weaned group was lower than that in control group.It is concluded as follows:1. It was a feasible strategy for Hu lambs to weaning at 28 d.2. ACTB was the best reference gene of relative q-PCR for Hu lamb small intestinal mucosal.3. Early weaning did good to the maturity of small intestine, but downregulated the expression of PepT1 in ileum at 42 d and SGLT1 in duodenum at 84 d.