Dried Watermelon Rind Mash Diet Increases Plasma L-Citrulline Level in Chicks

Abstract

Heat stress is an increasing concern in poultry industry as it can cause a rise in the body temperature of chickens. Recently, we reported that L-citrulline (L-Cit) is a potential hypothermic agent that could improve thermotolerance in chicks. However, synthetic L-Cit has not yet been approved for inclusion in animal diets. L-Cit was first isolated from watermelon. Watermelon rind (WR), an agricultural waste product, contains more L-Cit than the flesh of the fruit. In the current study, the chemical composition and L-Cit content of WR dried powder (WRP) were determined. WRP was mixed with water at a ratio of 4:5 (wt/v) to make WRP mash, and then mixed with a commercial starter diet to prepare a 9% WRP mash diet. The WRP mash diet was fed to 3-to 15-day-old chicks and daily food intake, body weight, and changes in rectal temperature were measured. At the end of the experiment, blood was collected from the chicks to analyze plasma L-Cit and other free amino acids. The chemical analysis of WRP revealed a variety of components including 19.1% crude protein. L-Cit was the most abundant free amino acid in WRP (3.18 mg/g). Chronic supplementation of the WRP mash diet significantly increased compensatory food intake, plasma L-Cit, L-ornithine, and L-tyrosine in chicks. WRP mash diet did not affect the body temperature of the chicks. In conclusion, WRP mash diet supplementation increased plasma L-Cit concentration in chicks. The increase in plasma L-Cit concentrations suggest that WR could be used as a natural source of L-Cit in chicks to ameliorate the adverse effects of heat stress.

Dietary L-citrulline supplementation modulates nitric oxide synthesis and anti-oxidant status of laying hens during summer season

“…The utilization of watermelon rinds, as a rich source of citrulline, was shown to reduce rectal temperatures of chicks similarly as citrulline's actions, under ambient and heat stress temperatures [33]. Also, as a potential feed additive, watermelon rind supplementation increased plasma citrulline levels in chicks [34]. These ndings of L-Cit associated thermotolerance suggest the potential of L-Cit supplementation as a nutritional strategy that would assist in ameliorating summer heat stress.…”

Oral Administration of Watermelon Rind Extract to Induce Hypothermia in Chicks

“…The present study was based on our previous study of WR powder in chick diet (Nguyen et al, 2019) and WR juice administration (unpublished data). However, RT was not found to change significantly during the period.…”

“…However, RT was not found to change significantly during the period. We assumed that because WR powder contained high fiber content of 14.5% and WR powder mash diet contained 0.002 mmol of Cit/mg of food, chicks consumed 0.03 and 0.04 mmol of L-Cit when they were 6-and 15-day-old, respectively (Nguyen et al, 2019). Further, a 2-ml dose of WR juice was calculated to contain high water content of 82.8-88.2% (Pansy and Thin, 2011) and low Cit content of 0.002 mmol.…”

“…In our recent study, dried WR powder was fed as a diet supplement to 3-to 15-day-old chicks to examine its effect on their rectal temperature (RT) and food intake. Although RT did not significantly change under control thermoneutral temperature (CT; 30±1℃), food intake and plasma L-Cit increased significantly (Nguyen et al, 2019). We attributed these effects to the fact that WR powder contains fiber that dilute the L-Cit concentration in the WR powder.…”

Dietary L-Citrulline supplementation modulates nitric oxide synthesis and anti-oxidant status of laying hens during summer season

“…The utilization of watermelon rinds, as a rich source of L-Cit was shown to reduce rectal temperatures of chicks in a similar fashion as L-Cit administration both at control and heat stress temperatures (46). Also, as a potential feed additive, watermelon rind supplementation increased plasma citrulline levels in chicks (47).…”