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Effect of vitamin D3 supplementation on lysine utilization in growing rabbits

Author:
Elwakeel, E.A., Abd El-khalek, E., Abd El-Hady, A.M., Ahmed, M.G., Hassan, O.A.
Source:
Animal feed science and technology 2019 v.254 pp. 114221
ISSN:
0377-8401
Subject:
albumins, average daily gain, body weight, calcium, cholecalciferol, cholesterol, crude protein, diet, digestible dry matter, digestible protein, feed conversion, feed intake, lysine, mortality, nitrogen balance, organic matter, phosphorus, rabbits, somatotropin, urea, urine
Abstract:
The effect of vitamin D3 (VD3) on lysine utilization in growing rabbits was studied in two experiments (Exp.). In Exp. 1, 162 growing rabbits (491 ± 38 g) were fed basal diets containing 16% crude protein ad libitum. The treatments were varying levels of VD3 (0, 500, and 1000 IU) and lysine (5.5, 6, and 6.5 g/kg dry matter; DM) in a 3 × 3 factorial design with six replicates in each treatment occurring for 5 weeks, and the experimental units were the cages (3 rabbits/cage). Nine experimental VD3+lysine diets, (0 + 0), (0 + 0.5), (0 + 1), (500 + 0), (500 + 0.5), (500 + 1), (1000 + 0), (1000 + 0.5) and (1000 + 1), were formulated. A basal diet (0 + 0) was formulated to be deficient in lysine (5.5 g/kg DM) and VD3 (0.0 IU). Lysine significantly (P < 0.01) affected the final body weight (FBW), average daily gain (ADG) and feed conversion ratio (FCR) but did not affect feed intake. VD3 tended (P = 0.06) to improve the FCR with no significant effect on FBW and ADG. VD3 and lysine exhibited no effect on feed intake. The highest mortality rate (38.9%, 7/18) was observed for the 0 + 0 (control) treatment, and the lowest mortality rates of 5.6% and 0.0% were observed for the 1000 + 0 and 1000 + 0.5 treatments, respectively. Exp. 2, the nutrient digestibility and nitrogen balance trial, was conducted with 45 rabbits (n = 5/treatment) randomly chosen from Exp. 1. Rabbits were housed in metabolic cages for 8 d and offered 180 g/d of each respective diet described in Exp. 1. A significant VD3 × lysine interaction was observed for N intake (P < 0.05). VD3 tended to increase N intake (P = 0.08) and improved (P < 0.05) dry matter digestibility (DMD) and organic matter digestibility (OMD). Lysine increased (P < 0.05) N intake and retained N (P < 0.01), decreased (P < 0.01) urine N, and tended to improve crude protein digestibility (CPD) (P = 0.08) and OMD (P = 0.10). Lysine increased the plasma total protein (TP), albumin (Alb; P < 0.05) and calcium (Ca; P < 0.01) contents and decreased plasma cholesterol (Cho), while VD3 and lysine decreased the urea concentration. A significant (P < 0.01) VD3 × lysine interaction was observed for plasma phosphorus (P) and growth hormones (GHs). VD3 increased P (P < 0.01) and tended (P = 0.08) to increase GHs, whereas lysine decreased (P < 0.05) P at the 1.0 g level but caused a linear and quadratic (P < 0.05) increase in GHs. Overall, the supplementation of diets with VD3 did not improve lysine utilization in growing rabbits; however, lysine increased N intake, retained N, the FBW, and the ADG and improved the FCR.
Agid:
6544513