ABSTRACT
In recent years, there has been a growing focus on using herbal extracts as immune enhancers for aquatic species, replacing antibiotics. In the present study, the effects of dietary supplementation of Hericium erinaceus extract (HE) on growth, feed utilization, hematology, expression of immunity-related genes, and immune responses in Nile tilapia infected by Streptococcus agalactiae were examined. A total of 240 Nile tilapia with an average body weight of 17.28 ± 0.01 g were fed diets enriched with different levels of HE: 0 (HE0), 0.1 (HE0.1), 1.0 (HE1.0), and 5.0 (HE5.0) g/kg. The results showed that growth parameters, feed conversion ratio, and organosomatic indexes were not linearly or quadratically affected by HE supplementation. Fish fed HE0.1 and HE1.0 increased protein efficiency ratio and protein productive values with significant linear and quadratic effects of HE enrichment. In addition, dietary supplementation of HE quadratically increased whole-body protein content. Red blood cell, white blood cell, and hematocrit were linearly and quadratically increased by HE supplementation. HE also linearly and quadratically decreased LDL cholesterol and linearly decreased the total cholesterol levels. Stress markers, serum glucose, and cortisol levels were linearly and/or quadratically decreased in HE-fed fish. The relative mRNA expression of tnf-α, il-1ß, il-6, and il-10 were upregulated in the HE0.1 and HE1.0 groups, while dietary supplementation of HE significantly decreased hsp70cb1 mRNA expression in all groups. After feeding dietary HE supplementation for 10 weeks, fish were intraperitoneally injected with pathogenic S. agalactiae. A high survival after challenge was found in all HE supplementation groups with the highest percent survival observed in the HE1.0 and HE5.0 groups. Our findings represent that supplementation of 1 g/kg of HE (HE1.0) could obtain the greatest effects on immunity and survival of Nile tilapia. In addition, the present study also showed that dietary supplementation of HE can improve protein utilization, hematology, expression of genes related to immunity, stress markers, and resistance of Nile tilapia against pathogenic bacterial infection.
ABSTRACT
The anthropogenic and climate-driven rise in water temperature is expected to have an effect on the physiological functions of ectothermic species. In the present study, hybrid catfish were subjected to three different temperatures (27, 32, and 37 °C) for 50 days to examine the effect of long-term exposure to high temperatures on growth and physiological parameters. The results showed that acclimation temperature improves growth and feed utilization with a quadratic effect (P < 0.05). The highest performance was observed at 32 °C, but fish acclimated at 37 °C decreased growth and feed utilization. In addition, skin darkening was observed in fish acclimated with increasing temperatures. Fat content of whole-body, liver, and dorsal muscle of fish was decreased by increasing temperatures (P < 0.05). Higher temperature levels significantly increased in all blood parameters (P < 0.05), except for high-density lipoprotein cholesterol, which was quadratically decreased (P = 0.004). Fish acclimated with increasing temperature also altered gill and liver histology such as gill shortening, hyperplasia and edema in the connective tissue, severe hyperplasia of epithelial cells, and desquamation, hepatocyte vacuolization, nuclei displacement, and pyknotic hepatic cells. While mucus cells were periphery distributed in the subcutaneous skin. In addition, cuboidal shape-like of club cells and melanophores were also observed in fish acclimated at 37 °C resulting in increased epithelial layer thickness. After fish subjected to increasing temperature exhibited an increase in the number of operculum movement and number of gasping for air (P < 0.05) in all acclimated groups. While fish challenged at 37 °C showed higher critical thermal maximum (CTmax, 41.33 °C) than those of the other groups. Overall, the maximum temperature (37 °C) may rick to hybrid catfish. To prevent physiological damage to the fish, as well as reduction of growth and productivity, the temperature in the aquaculture setting should be kept below 37 °C.
Subject(s)
Catfishes , Heteroptera , Acclimatization/physiology , Animals , Catfishes/physiology , Hot Temperature , Hyperplasia , TemperatureABSTRACT
In some geographical areas and in certain breeding situations, the interpretation of increased gain in the bovine is difficult to investigate. Due to their inherent genetic variations, their energy and protein needs vary as a function of inherent genetic differences, making these requirements difficult to accurately assess in bull species, e.g., Thai swamp buffalo. The study aimed at investigating and predicting protein requirement systems, by the provision of an abundant energy intake of 2.2 Mcal/kg DM for the maintenance and growth of Thai swamp buffaloes using a comparative prolonged feeding trial for 90 days. Sixteen bull Thai swamp buffaloes at the initial (Age: 18-24 months; BW: 233 ± 25.0 kg) were assigned into four treatment groups, four buffaloes each, fed 5.4, 6.6, 8.5, and 10.5% DM crude protein (CP). CP intake, BW, and physiological fluid were determined. The net CP requirements for maintenance and growth of Thai swamp buffaloes were 5.41 g CP/kg W0.75 and 0.46 g CP/g average daily gain (ADG), respectively. Our results indicated that CP requirement increases when the BW increases. An increased dietary CP resulted in increased amounts of blood urine nitrogen (N), N absorption, total volatile fatty acid, urinary purine derivative, and the microbial N. Notably, the net CP requirement for growth of Thai swamp buffalo was higher than it reported in NRC, but the maintenance was lower.