Secondary Functions of Arginine and Sulfur Amino Acids in Poultry Health: Review

Abstract

Amino acids such as arginine, methionine, and cysteine are the precursors of essential molecules that regulate growth and health, being classified as functional amino acids. This review describes the metabolism of arginine and the sulfur amino acids and how they modulate, directly or indirectly, different tissues. Emphasis is placed on their effects in supporting health during challenging conditions, such as heat stress and Eimeria infection. The use of arginine has been shown to reduce abdominal fat pad in ducks and increase lean tissue and bone mineral density in broilers. Additionally, the sulfur amino acids have been shown to improve bone development and are beneficial during heat stress. The use of L-methionine increased the cortical and trabecular bone mineral densities, in laying hens. Moreover, the dietary inclusion of these amino acids could reduce the damage caused by Eimeria spp. infection by regulating the antioxidant system and cell repair. Understanding how these amino acids can mitigate stressful conditions may provide us novel insights of their use as nutritional strategies to modulate the health status of chickens.

Increased Dietary Inclusion Levels of Lysine Are More Effective than Arginine in Supporting the Functional Status of the Gut in Growing Turkeys

“…Thus, it seems that the Lys:Arg ratio may play a significant role in the above process, and a shift from the optimal ratio may have adverse effects on microbiota activity and the physiological function of the gut. The observed effect is more evident when both AA are supplied at low levels, which has been documented in different poultry species [ 37 , 38 , 39 ]. Protein, including resistant dietary protein, microbial protein and protein that escaped digestion, synthesized by the host, may reach the ceca and be taken up by protein-fermenting bacteria.…”

Nutritional and Volatile Characterisation of Milk Inoculated with Thermo-Tolerant Lactobacillus bulgaricus through Adaptive Laboratory Evolution

“…The increase in arginine may be explained by the high yield of glutamic acid [ 58 ] and the pH being high in the inoculated milk produced by the thermo-tolerant strain, which favours arginine production [ 59 ]. Arginine and methionine are classified as functional amino acids that helps with immune defense and as antioxidant [ 60 ]. One of the primary roles of L. bulgaricus is to hydrolyse milk protein, casein, which degrade into peptides and FAAs.…”

Advances in the Nutrition of Functional Amino Acids in Healthy and Immunologically Challenged Birds

“…1.24, 1.34, and 1.44%) and challenge with Eimeria sporulated oocysts at 12 days of age, showed better ADWG and FCR at 14 days postchallenge at 1.14% Arg. Higher levels of Arg (1.34%) improved the intestinal permeability at five d postchallenge and the tight junction proteins zonula occludens-1 and zonula occludens-2 at six d postvaccination, while the addition of 1.44% Arg increased the zonula occludens-1 and zonula occludens-2 at 14 days postvaccination [16]. In chicks also housed in cages from 1 to 21 days, added with 1.11, 1.33, and 2.01% dietary Arg and challenged with a coccidiosis vaccine at 14 d of age, showed similar ADWG regardless of the dietary Arg level and lower FCR at 1.33% Arg.…”

“…In addition to this, it has been documented that the addition of Arg either in ovo or dietary Arg above the recommended level improves the digestive physiology and the cellular and humoral immune responses in nonchallenged and challenged birds; hence Arg has gained the distinction of belonging to the group of functional nutrients. The readers are referred to several comprehensive reviews about this topic [14][15][16][17][18]. In the next section, the recent findings on Arg feeding from in ovo to unchallenged and challenged broilers will be presented with emphasis on simultaneous effects on immunity/digestive physiology and productivity.…”