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Abstract

We conducted a 71-day experiment to investigate the effects of stocking density in a recirculating aquaculture system (RAS) on the growth performance, body composition, digestive activity, and blood biochemical parameters of the marbled eel Anguilla marmorata. We stocked marbled eel in 1.0 m 3 tanks at stocking densities of 12, 20, and 28 kg/m 3 , which were designated the low-density (LD), medium-density (MD) and high-density (HD) groups. The fish weighed 169.72 ± 2.75 g at the baseline level. Results revealed that the fish in the LD and MD groups had a higher ash content than fish in the HD group. The crude lipid content was significantly lower in the MD and HD groups than in the LD group. The protease activities in the stomach and intestine did not differ among the three groups. The total protein and aspartate aminotransferase levels were higher in the LD group than in the MD group. The alanine aminotransferase level was significantly lower in the LD group. These results indicate that a greater increase resulted in stress and significantly affected the growth of the fish. The optimum stocking density of A. marmorata can be achieved at 20.0 kg/m 3 in a RAS.

Effect of dietary l‐carnitine supplementation and energy level on oxidant/antioxidant balance in laying hens subjected to high stocking density

“…When hens are exposed to overcrowding stress, they have greater energy requirements and plasma protein mobilization increases according to the intensity of the stress to meet energy demand. In response to stress, the total protein content in the blood may have been used as energy (Tan et al, 2018). As these enzymes are protein, the reduction in the activities of these enzymes in this study may be due to decreased protein content in the blood during high stocking.…”

“…Consistent with our results, Sahin et al (2014) indicated that high stocking density decreased hepatic SOD, CAT and GSH-Px activities in rainbow trout. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015;C. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015;C.…”

“…It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015;C. In response to stress, the total protein content in the blood may have been used as energy (Tan et al, 2018). When hens are exposed to overcrowding stress, they have greater energy requirements and plasma protein mobilization increases according to the intensity of the stress to meet energy demand.…”

“…In addition, Simsek et al (2009) found that high stocking density decreased GPx activity, but not changed serum CAT activity. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015; C. Tan, Sun, Tan, Guozhi, & Xiaoling, 2018). When hens are exposed to overcrowding stress, they have greater energy requirements and plasma protein mobilization increases according to the intensity of the stress to meet energy demand.…”

Effet de la densité de mise en charge sur les performances zootechniques et la production chez les alevins de <i>Parachanna obscura</i> élevés en milieu contrôlé

“…Son élevage en système intensif permettra de conserver, renforcer les stocks naturels et produire continuellement des spécimens de taille commerciale destinés à la vente sur les marchés. Dans les systèmes d'élevage intensifs, plusieurs facteurs à savoir la quantité et la qualité de l'aliment (Erondu et al, 2006) et la densité de mise en charge des poissons (Schram et al, 2006 ;Wirat, 2011 ;Chattopadhyay et al, 2012 ;Tan et al, 2018) influencent le taux de survie, la croissance, l'efficacité alimentaire et la production. La connaissance des besoins nutritionnels et des densités optimaux de mise en charge des alevins permettent d'améliorer la production et la rentabilité économique en aquaculture (Fiogbé et Kestemont, 2003 ;Aksungur et al, 2007;de Oliveira et al, 2012 ).…”