Diets Se1, Se3, and Se9 resulted in a higher feed conversion ratio in fish, but with lower nitrogen and phosphorus retention compared to fish fed diet Se12. Whole-body, vertebral, and dorsal muscle selenium levels were elevated by dietary selenium yeast supplementation, escalating from 1 mg/kg to 9 mg/kg. Fish receiving Se0, Se1, Se3, and Se9 diets excreted less nitrogen and phosphorous waste than the fish receiving diet Se12. Fish nourished with Se3 demonstrated the most robust activity of superoxide dismutase, glutathione peroxidase, and lysozyme, accompanied by the lowest level of malonaldehyde in both liver and kidney. Our findings, derived from a nonlinear regression analysis of specific growth rate (SGR), indicated that a dietary selenium requirement of 1234 mg/kg is optimal for triangular bream. The diet containing 824 mg/kg of selenium (Se3) closely matched this optimal level and exhibited superior growth, feed utilization, and antioxidant capacity.
An 8-week feeding study was conducted to examine the influence of substituting fishmeal with defatted black soldier fly larvae meal (DBSFLM) on Japanese eel, encompassing growth performance, fillet texture, serum biochemical markers, and intestinal morphology. GS-9973 inhibitor Six diets, maintaining isoproteic (520gkg-1), isolipidic (80gkg-1), and isoenergetic (15MJkg-1) characteristics, were developed. Fishmeal replacement levels included 0% (R0), 15%, 30%, 45%, 60%, and 75% (R75). DBSFLM did not affect the growth performance, feed utilization efficiency, survival rate, serum liver function enzymes, antioxidant ability, or lysozyme activity of fish (P > 0.005). However, a notable decline was observed in the crude protein and the binding strength of the fillet in groups R60 and R75, concomitant with a substantial increase in fillet hardness (P < 0.05). The R75 group saw a significant decrease in intestinal villus length, and the goblet cell densities in the R45, R60, and R75 groups were all significantly lower, achieving statistical significance (p < 0.005). High DBSFLM levels, while not affecting growth performance or serum biochemical parameters, produced significant modifications in fillet proximate composition, texture, and intestinal histomorphology (P < 0.05). To achieve optimal performance, 30% of fishmeal can be replaced with 184 grams per kilogram of DBSFLM.
Improved fish diets, the driving force behind the development of finfish aquaculture, are predicted to maintain their significant contribution to fish growth and health. Strategies to effectively translate dietary energy and protein into fish growth are significantly desired by fish cultivation specialists. Beneficial gut bacteria populations can be fostered in humans, animals, and fish by incorporating prebiotic supplements into their diets. The investigation currently underway aims to uncover affordable prebiotic compounds exhibiting high potency in promoting the absorption of nutrients from food by fish. Nile tilapia (Oreochromis niloticus), a leading cultured fish species globally, had several oligosaccharides evaluated for their prebiotic effect. Fish nourished with differing diets underwent evaluation for several parameters, encompassing feed conversion ratios (FCRs), enzymatic activity, the expression of genes associated with growth, and the microbial ecology of their guts. In this research, fish of two distinct age groups, 30 days and 90 days, were utilized. Fish consuming diets supplemented with xylooligosaccharide (XOS), galactooligosaccharide (GOS), or a combination thereof demonstrated a significant decrease in feed conversion ratio (FCR) across both age groups. Thirty-day-old fish fed XOS and GOS diets demonstrated a 344% improvement in feed conversion ratio (FCR), compared to the control group. For 90-day-old fish, the application of XOS and GOS led to an impressive 119% decrease in feed conversion ratio (FCR); the combined prebiotic treatment demonstrated a more substantial reduction, decreasing FCR by 202% in comparison to the control group. GS-9973 inhibitor Fish exhibited enhanced antioxidant processes, as indicated by the elevated production of glutathione-related enzymes and the enzymatic activity of glutathione peroxidase (GPX), following XOS and GOS administration. The fish gut microbiota experienced substantial shifts in response to these advancements. The abundance of Clostridium ruminantium, Brevinema andersonii, Shewanella amazonensis, Reyranella massiliensis, and Chitinilyticum aquatile was enhanced by the inclusion of XOS and GOS. GS-9973 inhibitor Applying prebiotics to younger fish, as suggested by the findings of this study, could yield improved results, and the administration of multiple oligosaccharide prebiotics may lead to a more substantial increase in growth. Potentially utilizing identified bacteria as future probiotic supplements may improve tilapia growth, feeding efficiency, and, subsequently, reduce the overall cost of tilapia aquaculture.
Evaluating the influence of stocking densities and dietary protein content in biofloc systems is the objective of this research on the performance of common carp. Fish (1209.099 grams) were distributed among 15 tanks for a biofloc system study. Medium-density fish (10 kg/m³) were fed diets containing either 35% (MD35) or 25% (MD25) protein. High-density fish (20 kg/m³) received either 35% (HD35) or 25% (HD25) protein diets. Meanwhile, a control group at medium density in clear water consumed a 35% protein diet. The 60-day period of observation concluded with a 24-hour application of crowding stress (80 kg/m3) to the fish. Within the MD35 area, the fish growth rate was highest. Relative to the control and HD groups, the MD35 group displayed a smaller feed conversion ratio. In the biofloc groups, the activities of amylase, lipase, protease, superoxide dismutase, and glutathione peroxidase were found to be significantly higher than in the control group. Biofloc treatments, following periods of crowding stress, exhibited a substantial reduction in cortisol and glucose levels compared to the control group. Lysozyme activity in MD35 cells was notably lower than that of HD treatment groups after periods of 12 and 24 hours of stress. The biofloc system, augmented by MD, shows promise for enhancing fish growth and resilience to acute stress. MD-reared juvenile common carp can maintain optimal growth with a 10% reduction in protein content in their diets, when a biofloc system is integrated.
This research endeavors to establish the optimal feeding interval for tilapia fry. 24 containers were randomly filled with a total of 240 fishes. A daily feeding regimen was structured around six frequencies—4 (F4), 5 (F5), 6 (F6), 7 (F7), 8 (F8), and 9 (F9) times per day. The weight gain demonstrated a statistically significant elevation in groups F5 and F6 when juxtaposed with group F4; p-values of 0.00409 and 0.00306 were determined for F5 and F6, respectively. The treatments did not produce varying results for feed intake and apparent feed conversion (p = 0.129 and p = 0.451). Concerning water quality, the nitrogen concentrations in the treated water varied significantly between treatment groups F4 and F5 (p = 0.00478), F4 and F6 (p = 0.00283), and F4 and F9 (p = 0.00432) as well as P between F4 and F6 (p = 0.00215). The x² test indicated a relationship between feed frequencies and muscle fiber frequency, with a statistical significance (p < 2.2 x 10⁻¹⁷). Predominant fibers measured 10-20 micrometers in F4, F5, F6, and F7, and 30-40 micrometers in F8 and F9. While the area of hepatocytes differed only between F5 and F9, there was no corresponding variance in the nucleus area. A 10% difference in net revenue was observed between F5 and F4 (p = 0.00812), and between F6 and F4 (p = 0.00568). In summation, fingerlings fed five to six times a day showcase superior zootechnical and partial culinary practices.
The effects of incorporating Tenebrio molitor (TM) larval meal into diets on cytoprotective abilities, cell death pathways, antioxidant capabilities, and intermediate metabolic processes in the hearts, muscles, and digestive systems of gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) are investigated in this study. Three distinct experimental diets were designed, varying the inclusion of TM levels from 0% to 50%, in 25% increments. Both species exhibited a noticeable induction of Heat Shock Proteins (HSPs) within their muscle tissue when inclusion reached 50%. Oppositely, both species' muscle and digestive tracts displayed a significant (p < 0.05) elevation in p44/42 Mitogen-Activated Protein Kinase (MAPK) activation when the inclusion rate was 25%. Regarding the apoptotic cascade, the inclusion of TM had no impact on gilthead seabream; however, autophagy might have been suppressed in the muscle. The European sea bass's muscle and digestive tract demonstrated a substantial level of apoptosis, statistically significant (p < 0.05). Both fish species' cardiac function seemed to be more dependent on lipids than on the lipid demands from muscle or digestive tract. A difference in antioxidant activity was observed between gilthead sea bream and European sea bass; the latter displayed a statistically significant (p<0.05) increase at 50% TM inclusion. Species- and tissue-specific cellular responses induced by diet are illuminated by the current data, while European sea bass exhibits a greater vulnerability to TM inclusion.
To evaluate the effects of thymol (TYM) on growth, digestive performance, immune response, and resistance to Streptococcus iniae infection, dietary levels of 0, 1, 15, 2, and 25g/kg were utilized in this study with rainbow trout, Oncorhynchus mykiss. A study involving 450 fish (weighing approximately 358.44 grams each; mean ± standard deviation) was conducted across three replications. These were allocated to 15 tanks, with 30 fish per tank, and fed TYM over a 60-day period. After the feeding phase, the fish that were fed 15-25g TYM showcased superior growth, heightened digestive enzyme activity, and augmented body protein content in contrast to other dietary groups (P < 0.005).