Cross-effects of dietary probiotic supplementation and rearing temperature on growth performance, digestive enzyme activities, cumulative mortality and innate immune response in seabass (Dicentrarchus labrax)

Abstract

Probiotic influence on fish immune response and digestive capacity is extensively discussed in aquaculture. In this experiment, a feeding trial was carried out for 100 days to evaluate the cross-effects of probiotic supplementation and rearing temperature (17, 20 and 23°C) in juvenile seabass (Dicentrarchus labrax). The experimental diet was supplemented with a commercial probiotic blend (Biomin AquaStar Growout) at 3 g/kg diet (5.23 × 10 8 CFU/kg diet), and tested against a non-supplemented diet (control).Growth performance and innate immune responses were analysed at 70 and 100 days of feeding, whereas digestive enzyme activities were determined at 100 days of feeding. At the end of the feeding trial, fish were subjected to a handling stress and cumulative mortality was recorded. Digestive enzyme activities were influenced by temperature, with α-amylase and lipase activities peaking at the higher temperature (23°C) and trypsin at the lower temperature (17°C). Immune parameters showed a significant temperature versus feeding duration effect, with complement system (ACH50) and peroxidase peaking at 70 and 100 days of feeding, respectively.Poststress cumulative mortality was higher at the lowest temperature (17°C), especially in fish fed the control diet. In conclusion, water temperature was the main variable affecting the studied parameters, whereas the dietary probiotic supplementation had influence on the chymotrypsin activity and survival rate in seabass reared at 17°C. K E Y W O R D SDicentrarchus labrax, digestive enzymes, innate immune, probiotics, temperature Finally, in this study, we aimed to determine the effects of dietary probiotic supplementation on growth performance (final body weight, feed conversion ratio, daily growth index and protein efficiency ratio), immune system response (ACH50, lysozyme and peroxidase), digestive enzyme activities (α-amylase, lipase, trypsin and chymotrypsin) and stress-caused cumulative mortality, in seabass reared at three temperatures (17, 20 and 23°C) for 100 days. | INTRODUCTION | MATERIALS AND METHODS All | Experimental designThe experimental system was composed of 18 tanks with 80-L capacity each connected to a single recirculation system (TMC | Animals and dietsSeabass juveniles (12.7 ± 0.4 g) were purchased from a hatchery company situated in Gravelines, France. After arrival to the fish rearing facility, seabass were kept in quarantine for 15 days. Then, they were transferred to the experimental recirculation system, individually weighed and equally distributed into 18 tanks (26 fish/ tank) at a density of 3.4 kg/m 3 .The basal diet formulation was used as control diet (Table 1) the duration of the feeding trial, as recommended by the producer.The CFU counts of the diets were performed before and after the trial.Diets were prepared according to the normatives ISO 6887-1:1999, ISO-7218:2007 and ISO 6498:2012 considering the guidelines for microbiological sample preparation of food and animal feeding stuffs.Thereafter, the quantification of bacteria ...

Interaction Between Dietary Lipid Level and Seasonal Temperature Changes in Gilthead Sea Bream Sparus aurata: Effects on Growth, Fat Deposition, Plasma Biochemistry, Digestive Enzyme Activity, and Gut Bacterial Community

“…Before the temperature change, trypsin level was slightly higher at 17 • C in each diet; then after the thermal switch, its activity displayed higher values at 23 • C but relative decreasing changes ranging from 40 to 59% were observed for all the treatment. Our trypsin levels found before thermal change are consistent with results found in European sea bass (Dicentrarchus labrax) reared at three different water temperatures (17, 20, and 23 • C) where the trypsin activity peaked at the lowest temperature of 17 • C (Pereira et al, 2018). Temperature and dietary lipid level also affected FI, which could have resulted in variation of enzymatic activity.…”

“…In the present study, chymotrypsin activity was influenced only by diet, being more elevated in fish fed 21% dietary lipid level rather than 16% both before and after temperature change. Similarly, while temperature did not affect chymotrypsin, dietary regime was shown to improve consistently its activity in European sea bass reared at 17 • C (Pereira et al, 2018). As regard amylase activity, while before the temperature change no dietary or thermal effect occurred, after the temperature switch, it was significantly impeded, with lower activity values and higher relative reduction in fish brought to 17 • C (HL).…”

Solid-State Fermentation of Plant Feedstuff Mixture Affected the Physiological Responses of European Seabass (Dicentrarchus labrax) Reared at Different Temperatures and Subjected to Salinity Oscillation

“…Water temperature greatly influences fish growth performance [65]. In this trial, the DGI positively correlated with rearing temperature, as previously reported for seabass [66,67]. However, TGC was not affected by water temperature nor by salinity, confirming the adequacy of the TGC model to determine the effects of different diets of fish maintained under different environmental conditions [68].…”

Host-Associated Probiotics: A Key Factor in Sustainable Aquaculture

“…To our knowledge, commercial probiotics have been used in aquaculture since the early 80ties (Boyed et al, 1984) and until today (e.g. Zheng et al, 2017;Zhou et al, 2017;Interaminense et al, 2018;Pereira et al, 2018). However, recently, attention has focused on using hostmicrobiota as a probiotics source (e.g.…”