Impact of polyacrylamide supplementation on intake, nutrient digestion and growth of lambs

This study was conducted to evaluate the effect of polyacrylamide (PAM) supplementation on the intake, digestion, weight gain, metabolism and growth of lambs. A total of ten 30 days old male small-tailed Han lambs with a body weight of 7.7±0.5 kg were divided into two equal groups (n = 5 each) and fed a basal diet or diet supplemented with 2.0 g of PAM per kg diet. The duration of the experiment was 210 days and experimental diets were fed ad libitum throughout the experimental period. Voluntary feed intake (VFI) was measured on daily basis, while body weight was measured on every ten days of the experiment.Two digestive and metabolic trials were conducted at the lamb's age of 95 to 103 days (Trial 1) and at the age of 210 to 218 days (Trial 2). At the end of experiment, all lambs were slaughtered to determine carcass characteristics. Results of the current study showed that supplementation of PAM in the diet of lambs increased the VFI and daily body gain by 14.4% (P < 0.05) and 15.2% (P < 0.01), respectively. In Trial 1, PAM supplementation in the diet increased the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), cellulose, energy, and nitrogen retention by 7.9%, 5.4%, 6.4%, 9.6%, 4.3% and 30.3% (P < 0.01), respectively, and in Trial 2, PAM supplementation in the diet increased the digestibility of DM, OM, CP, cellulose, energy, and nitrogen retention by 9.3%, 7.9%, 7.7%, 11.6%, 6.9% and 38.5% (P < 0.01), respectively. Results of carcass parameter explored that supplementation of PAM in the diet increased the carcass, net meat and lean meat weights by 24.5%, 25.5%, and 30.6% (P < 0.01), respectively, however, PAM supplementation in the diet did not influence the contents of DM, OM, or CP in fresh liver, leg muscle, and rumen tissue; in addition, the CP contents in the Longissimus dorsi muscle was decreased by the supplementation of PAM in the diet. In summary, supplementation of 2.0 g of PAM per kg diet increased the VFI, nutrient digestibility, nitrogen retention, and carcass yield of lambs.