Effects of DL-methionine supplement on growth performance and amino acid digestion and plasma concentrations in sika deer calves (Cervus nippon)

Abstract

This experiment was set to investigate the effects of DL-methionine (DL-met) supplement on growth performance and amino acid digestion and plasma concentrations in sika deer calves. Twelve healthy 5-month-old sika deer (29.44 ± 2.86 kg initial bodyweight) were randomly divided into three groups (4/group) and one sika deer per replicate. Levels of Met supplement in three treatments were 0, 1 g/kg and 2 g/kg, respectively. The results showed that the average daily gain for the early 35-day study period tended (P = 0.07) to increase linearly as the Met supplement increased, the feed to gain ratio (F : G) for the early period decreased (linearly and quadratically, P < 0.05), and, in the late 35-day study period, tended (linearly, P = 0.08) to decrease as dietary Met increased. The apparent digestibility of Met increased (linearly and quadratically, P < 0.01) with graded amounts of supplemental Met, and the apparent digestibilities of valine, leucine, isoleucine, phenylalanine, glycine, aspartic and cystine showed a linear increase (P < 0.05). Plasma glycine, proline and isoleucine concentrations increased linearly and quadratically (P < 0.01) with Met supplementation, plasma serine and leucine increased linearly (P < 0.05), and plasma histidine, lysine, arginine and NH3 increased quadratically (P < 0.01 or P < 0.05), with graded amounts of supplemental Met. Met supplementation in the diet improved feed utilisation and amino acid (AA) nutrient digestion, and affected plasma AA concentrations in sika deer calves.