The effect of post-ruminal infusion of protein or energy on the pathology of Trichostrongylus colubriformis infection and body composition in lambs

M.D. Bown, D.P. Poppi and A.R. Sykes

Animal Science Group, Lincoln University, Canterbury

Proceedings of the New Zealand Society of Animal Production. 1986, 46: 27-30

Mean live-weight gain ± s.e.m. over the 12-week experimental period was 8.0±0.9; 6.9±1.0; 3.7±0.9; 3.1±0.7 kg for C, PI, EI and SI respectively. Protein infusion reduced mean faecal egg output (PI, 1.30±0.57; EI, 2.85±1.08; SI, 2.01±0.37 x 10 6 eggs/d) and mean total parasite burden at slaughter (PI, 18000±543000; EI, 46000±6700; SI, 39000±6700), though endogenous plasma loss into the gastro-intestinal tract was not affected (C, 73.3±44.3; PI, 251.6±1.2; EI, 281.5±95.3; SI 200.0±33.0 mol/d).

After increasing for 4 weeks, dry matter intake of infected animals decreased by approximately 22% for PI and EI and by 32% for SI animals. Total ME intake (inclusive of infusions) was C, 0.607; PI, 0.687; EI, 0.704; SI, 0.617 MJME/W 0.75/d suggesting that ME intake o0f infected animals was not regulated by energy satiety. At slaughter the protein energy:total energy ratio in the empty body was similar for all groups (0.31), but the rate of energy retention over 12 weeks was different (C, 0.077 ±0.014; PI, 0.094±0.015; EI, 0.069±0.018; SI, 0.041±0.009 MJ/W 0.75/d). Nitrogen retention was increased 5-fold by protein infusion and was doubled by energy infusion. These results suggest that the effect of the parasite on the host is a result of increased irreversible loss of endogenous protein from the small intestine rather than catabolism of protein to supply energy, and that this effect can be alleviated by protein supplementation.

Keywords: NZSAPAB; Abomasal infusion; casein; glucose; body composition; Trichostrongylus colubriformis; endogenous plasma loss; worm burden