Biomedical subjects
Publications and source records attributed to Md Jisan Ahmed.
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BACKGROUND: Heat stress (HS) is a major environmental challenge for broilers, particularly under rising global temperatures and high humidity. Broiler chickens are highly susceptible because of their rapid growth rate, high metabolic heat production, limited thermoregulatory capacity and genetic selection for fast growth. OBJECTIVE: This review aims to synthesise current evidence, evaluate the effectiveness of existing mitigation strategies, identify key knowledge gaps and provide future research directions to improve broiler resilience, welfare and productivity under increasingly HS conditions. METHODS: This review synthesised evidence published between 2010 and 2025 on the physiological, metabolic, intestinal, immunological and productive consequences of HS and evaluated mitigation strategies. RESULTS: The reviewed studies demonstrate that HS reduces feed intake by approximately 10%-30%, suppresses body weight gain and feed efficiency and increases mortality, with severity depending on temperature, humidity and broiler genotype. HS disrupts carbohydrate, protein and lipid metabolism; induces acid-base imbalance and oxidative stress; compromises intestinal barrier integrity; alters gut microbiota; suppresses immune function; and reduces meat quality. Nutritional interventions, including dietary electrolyte balance, antioxidants, vitamins, selenium, zinc, phytogenic compounds, probiotics, betaine and optimised feeding strategies, environmental management and genetic approaches, including naked-neck and frizzle genes, can partially alleviate these adverse effects. However, inconsistencies among studies persist because of differences in broiler strains, environmental conditions, dietary formulations and experimental protocols. CONCLUSION: HS substantially compromises broiler health, welfare, productivity and meat quality. Nutritional, environmental and genetic approaches can partially mitigate its adverse effects; however, further research is needed to improve broiler resilience under increasingly HS conditions.
BACKGROUND: Amino acids are fundamental in sustaining physiological homeostasis during stress conditions. l-citrulline (l-Cit), a non-essential amino acid (NEAA) and metabolic precursor of arginine, has been reported to exert beneficial effects on the health and performance of broiler chickens. OBJECTIVE: This study aimed to investigate the effects of dietary supplementation with varying inclusion levels of l-Cit on growth performance, meat quality, plasma biochemical indices, and thermoregulatory responses in broiler chickens. METHODS: A total of 120 one-day-old chickens of the Lohman meat (Indian River) strain were randomly allocated to four dietary treatments, and each treatment included 30 birds in 3 replicates each. A 7-day feeding trial was conducted, beginning at 21 days of age. The control group (T0) was fed only a basal diet, while l-Cit was administered through the drinking water at concentrations of 0.5 % (T1), 0.75 % (T2), and 1.0 % (T3) to the respective treatment groups, in addition to the basal diet. RESULTS: Dietary inclusion of l-Cit significantly affected broiler performance and physiology. The T2 group demonstrated the highest body weight gain and lowest feed conversion ratio (FCR) compared with T0, T1, and T3 (p < 0.05). Organ development was increased in T2, with significant increases in bursa, heart, and liver indices, alongside reduced abdominal fat (p < 0.05). Meat quality improved through reduced drip loss and elevated muscle pH, particularly in T2. Plasma biochemical analysis showed lower cholesterol, triglycerides, and LDL in all l-Cit groups, with optimal in T2 (p < 0.05), while HDL and uric acid remained unaffected. Moreover, rectal temperature decreased significantly across l-Cit groups (p < 0.05). CONCLUSION: Overall, this study suggests that a diet supplemented with 0.75 % l-Cit (T2), which could be a promising amino acid without affecting meat quality or consumer preferences, may improve growth performance, meat quality, the lipid profile (blood plasma), and thermoregulation in broilers.