Phosphorus effect on weight gain in rats fed wheat gluten diets -

Abstract

Wheat gluten is the major protein source in many developing countries. Gluten lacks some essential amino acids, primarily lysine, and, accordingly, can’t foster optimal growth. For that reason, it should be complemented with a protein source containing the limiting amino acid to improve growth. Wheat is also known to contain limited amounts of available phosphorus. In a recent study on rats (Hammoud et al., 2015), the addition of phosphorus to a low complete protein diet (10percent egg white protein) was reported to yield weight gain comparable to that of a normal protein diet (20percent). The objective of this study was to investigate the effect of phosphorus addition to a low incomplete protein diet on growth. After receiving approval from Institutional Animal Care and Use Committee (IACUC) of the American University of Beirut (AUB), forty male rats, of around 220 g, were randomly divided into four groups and maintained on diets containing 10percent protein in the form of wheat gluten (G) with added lysine (G+L) or phosphorus (G+P) or lysine plus phosphorus (G+L+P). Body weight and food intake were measured twice per week for 9 weeks. Food intake varied significantly when lysine or phosphorus were added to the diet. Food intake of the lysine or phosphorus groups increased by about 15percent, while that of both (lysine plus phosphorus) increased by about 45percent. Weight gain and energy efficiency were significantly different according to lysine, phosphorus and their interaction lysine x phosphorus. Around 5 times improvement was seen following the addition of either lysine or phosphorus, and this was further amplified to 20 times with the combination. In conclusion, enhanced growth following the addition of both lysine and phosphorus seems to be mainly related to efficient energy utilization rather than increased energy intake. Moreover, a combination of the missing amino acid plus phosphorus is required to improve the quality of a gluten based diet.