Assessment of zootechnical parameters, intestinal digestive enzymes, haemato-immune responses, and hepatic antioxidant status of Pangasianodon hypophthalmus fingerlings reared under different stocking densities

Abstract

A 3-month experiment was designed to investigate the effects of different stocking densities on growth, stress markers, intestinal digestive enzymes, hepatic antioxidant biomarkers, serum immunity, and survivability of striped catfish, Pangasianodon hypophthalmus. The relationship between fish stocking densities and water quality parameters was also assessed. Healthy fish (n = 1260 individuals, 17.52 ± 0.20 g) were raised in twelve fiberglass tanks. Triplicate fish groups with stocking densities of 60, 90, 120, or 150 fish per 1 m3 were designed, further referred to as SD60, SD90, SD120, and SD150 groups. Fish feeding was done using a commercially purchased well-balanced diet three times per day with a feeding rate of 3% of the wet fish weight. Results revealed that un-ionized ammonia, nitrite, and pH were significantly elevated, and dissolved oxygen levels were decreased significantly with increasing the stocking densities. The survival rates and growth significantly decreased with increasing fish stocking densities. The intestinal lipase, protease, trypsin, and amylase enzymes decreased significantly (P < 0.05) along with increased stocking densities. Moreover, significant decreases were noticed in total protein, lysozyme activity, and globulin levels when the stocking density was higher than 60 fish/m3. Conversely, serum stress biomarkers (such as blood glucose and cortisol), transaminases, alkaline phosphatase, and blood urea nitrogen were significantly elevated with increasing stocking densities. Hepatic CAT, SOD, and T-AOC were decreased; meanwhile, hepatic MDA levels were significantly increased, together with the stocking rates. In the end, we found that the SD150 group recorded the lowest growth rates, immune responses, and antioxidant capacity and the highest stress markers as blood glucose and cortisol. In this context, we can conclude that the stocking 60 fish/m3 resulted in better growth, survival, immunity, antioxidant status, and overall performances of striped catfish. Graphical Abstract

Growth Performance, Physiological Responses, and Histoarchitectural Changes in Juvenile Pangasianodon hypophthalmus under Different Environmental Salinities

“…This fish species is promising for culture and preferable to many fish farmers for several reasons, including its high growth rates, tolerance to environmental conditions, survivability and thriving in high stocking densities, acceptable taste, somewhat decreased production costs, and relatively high economic returns [18]. This fish has been recently introduced as an exotic species in Egypt; however, its suitability to be farmed in Egyptian farming conditions has not been established and confirmed until now [19][20][21].…”

Stocking Density of the Pangasius Hypophthalmus Reared in Raceway System

“…However, Chowdhury et al (2020) concluded that sh (P. hypophthalmus) growth performance declined with increasing stocking density. Zaki et al (2023) found that stocking at 60 sh/m 3 resulted in better growth, survival, immunity, antioxidant status, and overall performance in striped cat sh. On the other hand, Nageswari et al (2022) recommended a stocking density of 210-240/m 3 for P. hypophthalmus in a bio oc system.…”

“…Experimental design, facilities, and feeding For this study, 700 of the Pangasius hypophthalmus sh species were utilized, each with an initial weight of 527.91 ± 73.40 g. The experiment followed a completely randomized design with ve treatments and four replications, resulting in a total of 20 experimental units. The densities tested were as follows: 30, 50, 70, 90, and 110 sh/m³, which corresponded to 15,25,35,45, and 55 sh per box, respectively. The experimental units were comprised of circular blue polyethylene tanks with a volume capacity of 1000 L (1 m³), equipped with individual water supply systems, ow control mechanisms, and selfsiphoning capabilities.…”

Editorial: Functionality and applications of phytochemicals in aquaculture nutrition

“…If these conditions are not found, deterioration of the water quality parameters (particularly elevated un-ionized ammonia, nitrite, nitrate, organic matter, or decreased dissolved oxygen levels) will occur. Furthermore, the possibility of flourishing emergent diseases (bacterial, fungal, or viral) will occur and spread rapidly among the farmed fish (2). Deteriorated water quality will induce stressful environmental conditions, disrupt the physiological responses of the exposed fish, trigger immune suppression, compromise health, and consequently cause high mortalities.…”