Dietary effects of Saccharomyces cerevisiae and Allium sativum on growth, antioxidant status, hepatic and intestinal histoarchitecture, expression of growth- and immune-related genes, and resistance of Oreochromis niloticus to Aeromonas sobria.

This study investigated the benefits of yeast, Saccharomyces cerevisiae and/or garlic, Allium sativum supplementation in diets of Nile tilapia with regard to growth, antioxidant status, hepatic and intestinal histoarchitecture, expression of growth- and immune-related genes, and resistance to Aeromonas sobria infection. Fish (with an initial weight of 9.43 ± 0.08 g) were allocated to twelve hapas, organized into four triplicate treatment groups defined as control (no supplementation), yeast (4 g/kg diet), garlic (30 g/kg diet), and a mixture of both. This trial continued over a 60-day feeding period. Results revealed that combined treatment (yeast + garlic) demonstrated the most promising outcomes regarding growth, with significantly higher final body weights, weight gains, and specific growth rates compared to other groups. Moreover, this combination enhanced hepatic antioxidant status, as evidenced by elevated levels of reduced glutathione and activities of catalase and superoxide dismutase enzymes, reflecting improved defense against oxidative stress. Histological assessments of the livers and intestines demonstrated structural enhancements in yeast and garlic treatments, suggesting improvements in organ health. In comparison to the control, the gene expression analyses unveiled increased expression of growth-related (igf-1 and ghr1) and immune-related (il-10, lyz, and hep) genes in the test groups, indicating a possible reinforcement of the growth and immune responses. The combined treatment also showed the highest resistance to A. sobria infection, as evidenced by improved survival rates and lower mortality compared with the other groups. These findings highlight the benefits of a combination of both yeast and garlic as a dietary supplementation regimen. In conclusion, this study suggests that the combined treatment regimen could be considered an effective strategy to promote the health and productivity of Nile tilapia under production conditions.

Evaluation of different probiotics on growth, body composition, antioxidant capacity, and histoarchitecture of Mugil capito.

We investigated the dietary effects of the single application of Saccharomyces cerevisiae, Lactobacillus bulgaricus, and their combination on growth, proximate composition of whole fish body, antioxidant defense, and histoarchitecture of hapa-reared Mugil capito. Healthy fish (Fish weighed = 10.30 ± 0.10 g at first) were randomly allocated into 4 equal groups, each with three replicates. These groups were designed as follows: (1) a group fed a basal diet without probiotics (control), (2) a group fed a diet containing S. cerevisiae (4 g/kg diet), (3) a group fed a diet containing L. bulgaricus (2 g/kg diet), and (4) the last group fed a diet containing a combination of both, all for a duration of 60 days. Probiotic-treated groups showed significantly better growth and nutrition utilization than the control group. Significant differences were observed in the crude fat and crude protein contents among the groups, with the combination group exhibiting the highest levels. However, there were no significant variations in ash content across all groups. The highest hepatic antioxidant capacity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) enzyme activities) was observed in the combination group. Thiobarbituric acid reactive substance (TBARS) concentrations were decreased significantly in all probiotic groups, suggesting improved oxidative stress resilience in these groups. The histomorphological analysis of the hepatopancreatic tissues revealed well-arranged parenchyma, increased glycogen storage, and melanomacrophage centers in probiotic-treated groups, particularly the combined probiotics group. Furthermore, the probiotic supplementation improved the histoarchitecture of the intestinal villi compared to the control group. To put it briefly, combined dietary administration of these probiotics improved growth, body composition, antioxidant defenses, and hepatic and intestinal health in hapa-reared M. capito, highlighting their promising role in promoting welfare and productivity.

The influence of coconut oil on the growth, immune, and antioxidative responses and the intestinal digestive enzymes and histomorphometry features of Nile tilapia (Oreochromis niloticus).

The trials of finding non-conventional and alternative aquafeed ingredients are increasing. In this sense, this study evaluated the influence of coconut oil on the growth, feed utilization, immune, and antioxidative responses of Nile tilapia. Five test diets were formulated by mixing coconut oil with the other ingredients at 0, 1, 2, 3, and 4% of the total ration and presented for tilapia for 60 successive days. The final weight, SGR, weight gain (WG), and feed intake were superior in fish delivered 2% of coconut oil (P < 0.05). Concurrently, fish that received 2% coconut oil had lower FCR and higher PER than fish of the control and 4% groups (P < 0.05). Higher lipase activity was observed in fish of 2% and 3% levels than the remaining groups (P < 0.05). Besides, the amylase and protease activities of fish in 1%, 2%, and 3% groups were higher than the 0% level (P < 0.05). The total blood cholesterol, RBCs, and PCV showed higher values in Nile tilapia fed 2% and 3% coconut oil (P < 0.05). The lysozyme and phagocytic activities were higher in fish fed 2% and 3% levels than the control (P < 0.05), while the phagocytic index in 2% and 3% levels was higher than 0% and 4% levels. Furthermore, SOD and CAT were higher in fish fed 1%, 2%, and 3% than fish fed 0% and 4% levels while GSH was higher in fish of 1%, 2%, and 3% than fish fed 0% level (P < 0.05). However, the MDA level was markedly lower in fish fed 25, 3%, and 4% coconut oil than the 0% level (P < 0.05). The intestine's histological structure in all groups appeared normal, forming of intestinal villi projecting from the intestinal wall. Also, the structure of the hepatopancreas had a normal architecture in all groups. To sum up, the inclusion of coconut oil at 2 to 3% is recommended as a replacer for fish oil in Nile tilapia diets.

The impact of menthol essential oil against inflammation, immunosuppression, and histopathological alterations induced by chlorpyrifos in Nile tilapia.

Chlorpyrifos (CPF) is one of the predominant water pollutants associated with inflammation and immunodepression in aquatic animals. In this study, menthol oil (MNT) impacted the immunity, antioxidative, and anti-inflammatory responses against CPF toxicity in Nile tilapia. Fish fed two diets with or without MNT and placed in four groups (control, CPF, MNT, and CPF/MNT). After 30 days, fish fed MNT displayed higher growth performance and lower FCR than CPF-intoxicated fish without feeding MNT (P < 0.05). The survival rate of fish was reduced in the CPF group without MNT feeding (P < 0.05). Blood Hb, PCV, RBCs, and WBCs were decreased in fish by CPF toxicity, while the highest Hb, PCV, RBCs, and WBCs were observed in fish fed MNT followed by those fed the control without CPF toxicity (P < 0.05). Fish fed MNT had the highest total protein, albumin, and globulin, as well as the lowest urea, bilirubin, and creatinine after 15 and 30 days. However, fish under CPF toxicity had the most inferior total protein, albumin, and globulin, as well as the highest urea, bilirubin, and creatinine among the groups (P < 0.05). The enzyme activities of ALP and ALT displayed low levels by MNT with or without CPF exposure than fish fed without MNT with or without CPF exposure after 15 and 30 days (P < 0.05). The lysozyme and phagocytic activities displayed reduced levels by CPF without MNT feeding after 15 and 30 days, while increased activities were noticed by MNT feeding without CPF toxicity followed by fish fed MNT with CPF toxicity (P < 0.05). The transcription of CAT and GPX genes displayed upregulated levels in tilapia fed MNT and exposed to CPF (P < 0.05). Also, CPF toxicity increased the transcription of the IFN-γ gene but decreased the IL-8 and IL-1ß genes. The transcription of HSP70 displayed lower levels (P < 0.05) by CPF without supplementing MNT than fish fed MNT and exposed to CPF. Histopathological analysis revealed that inflammation existed in the liver, gills, and intestine of tilapia due to CPF toxicity while MNT protected tissues from inflammation. To conclude, MNT activated the immunity, antioxidative, and anti-inflammatory responses of Nile tilapia under CPF toxicity.