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.
Effects of salinity level on growth performance, feed utilization, and chromatic deformity of the hybrid Red tilapia, Oreochromis niloticus x O. mossambicus
