Carry over effects of dietary L-arginine on the immune system in chickens. (Abstract)

Abstract

8A Carryover effects of dietary L_arginine on the immune system in chickens K. Deng, C.W. Wong and J.V. Nolan School of Rural Science and Agriculture, Animal Science, University of New England, Armidale NSW 2351 kdeng3@metz.une.edu.au Chickens cannot biosynthesise arginine and many studies with other species have shown that immune responses can be influenced by dietary arginine. Additionally, as nutritional status in early life may permanently programme immune functions in later life of humans and other species (Hales and Barker 1992), the present study investigated the carryover effect of shortterm dietary arginine in early life on the immune system in chickens. Dayold ISABrown cockerels (n = 180) were allocated to 3 treatment groups, each with 6 replicates of 10 birds, and were given an arginine deficient basal diet (6.7 g arginine/kg) supplemented with 0 (control), 2.7 (LA) or 5.4 (HA) g Larginine/kg for 4 weeks; then all birds were offered a commercial pullet grower feed (8.9 g arginine/kg) for another 8 weeks. The dietary arginine contents of the control, LA and HA diets were equivalent to 70, 100 and 130% respectively of NRC, USA, recommendations. Lymphoid organ weights, serum primary antibody levels against sheep red blood cells (SRBC) and bovine serum albumin (BSA), and cutaneous reactivity of toewebs to phytohaemagglutinin (PHA)M as an indicator of T cell responsiveness, were measured at 4 week intervals. The Larginine supplementation increased (P<0.05) growth rates during the supplementary period (Table 1). At Week 4, no differences ( P>0.05) in lymphoid organ weights relative to bodyweight (BW), antiSRBC antibody levels or toeweb PHA responses were detected. These results were similar to those reported by Kidd et al. (2001). Although LAfed birds had lower (P<0.05) antiBSA IgG antibody levels than the control at Week 4, this effect did not persist (P>0.05) at Weeks 8 and 12 (Table 1). In contrast, while no difference (P>0.05) in the antiBSA IgM antibody levels was noticed at Week 4, the LAfed birds showed a higher (P<0.05) level at Week 12 than the control. Similarly, an increased (P<0.05) antiSRBC antibody level and a reduced (P<0.05) relative bursa weight in HAfed birds at Week 8 without any prior effects (P>0.05) were also evident. It is thus concluded that supplementation with Larginine in early life was able to enhance the antibody response at a later stage of young chickens, depending on the type of antigen. Hales, C.N. and Barker, D.J. (1992). Type 2 (noninsulin dependent) diabetes mellitus: the thrifty phenotype hypothesis. Diabetologia 35, 595601. Kidd, M.T., Peebles, E.D., Whitmarsh, S.K., Yeatman, J.B. and Wideman, R.F., Jr. (2001). Growth and immunity of broiler chicks as affected by dietary arginine. Poultry Science 80, 15351542. Table 1 Bodyweight (BW), lymphoid organ weights, serum primary antibody levels against SRBC and BSA, and toe_web PHA responses in chickens given a control, LA or HA diet during the first 4 weeks of age. Week 4 0 BW (g) Thymus (g/kg BW) Spleen (g/kg BW) Bursa (g/kg BW) Anti_SRBC titre (log titres) Anti_BSA IgM (unit/ml) Anti_BSA IgG (unit/ml) Toe_web PHA response (mm) a, b Week 8 HA 210b 2.92 1.59 3.48 0.60 1.43 2.03 ab Week 12 HA 685 3.65 1.90 3.82 0.95 b b LA 208b 2.84 1.72 3.54 0.55 1.39 1.66 b 0 667 3.83 1.79 4.86a 0.50 a LA 678 3.69 1.91 4.07 0.60 2.40 3.24 0.55 ab ab 0 1300 3.73 2.03 3.33 0.48 2.40 a LA 1296 3.76 2.33 3.34 0.55 2.92 b HA 1314 4.46 2.20 3.45 0.78 2.67 ab 194 a 2.91 1.61 4.08 0.63 1.64 2.23a 0.32 2.23 3.28 0.39 2.22 3.28 0.36 3.10 0.55 3.14 0.38 3.03 0.48 0.41 0.40 Means with different superscripts in the same row within the same age differ (P<0.05) Recent Advances in Animal Nutrition in Australia, Volume 14 (2003)