Aspergillus awamori positively impacts the growth performance, nutrient digestibility, antioxidative activity and immune responses of growing rabbits

Growth performance, digestive function, thyroid activity, and immunity of growing rabbits fed olive cake with or without Saccharomyces cerevisiae or citric acid

The present study investigated the impact of dietary inclusion of olive cakes (OC) with or without Saccharomyces cerevisiae (SC) and citric acid (CA) on growth, digestive function, thyroid activity, antioxidant status, immunity, and intestinal architecture of growing rabbits. One hundred forty 35-day-old male New Zealand white rabbits were randomly assigned into seven experimental groups with five replicates each, as follows: control (CN), fed the basal diet; OC20 and OC25, fed diets with 20 and 25% OC; OS20 and OS25, fed diets containing 20 and 25% OC with S. cerevisiae at 5 g/kg diet; OA20 and OA25, fed diets supplemented with 20 and 25% OC with 1.0% citric acid. No differences in live body weight, feed intake, feed conversion ratio, and carcass traits were noticed among experimental groups, while body weight gain and carcass (%) were increased (P < 0.05) in OS20 compared to the control. Digestibility coefficients of all nutrients and activities of amylase, cellulose, and trypsin did not differ in treated groups compared to the control except for OS20, which recorded enhancement in nutrient digestibility. Plasma triiodothyronine and thyroxine were elevated (P < 0.05), while triglycerides and cholesterol were reduced (P < 0.05) in OS20 compared to CN. Plasma concentrations of immunoglobulin M and G and superoxide dismutase were increased in treated groups compared to the control. Dietary inclusion of SC and CA improved rabbits' intestinal health, as the cecal Lactobacillus count was increased, E. coli count was decreased, and villus height was elevated in SC- and CA-treated groups. In conclusion, dietary incorporation of SC or CA enhanced the nutritional value of OC and improved growth performance, nutrient digestibility, thyroid activity, antioxidative status, and gut health of growing rabbits.

Ramifications of Heat Stress on Rabbit Production and Role of Nutraceuticals in Alleviating Its Negative Impacts: An Updated Review

Heat stress has become a widespread concern worldwide, which is a major environmental stress that causes substantial economic loss in the rabbit industry. Compared to other agricultural animals, rabbits are more sensitive to heat stress as they have fewer sweat glands and a thicker coat of fur, increasing the heat dissipation complexity. Thus, heat stress hurts rabbits' productivity, meat quality, reproductive performance, antioxidative properties, immune responsiveness, intestinal histomorphology, and microbiome. Nutraceuticals include vitamins, minerals, antioxidants, organic acids, fatty acids, probiotics, prebiotics, synbiotics, enzymes, and medicinal plants due to the possible impacts on maintaining common biological situations, strengthening immune response, and preventing illness, which ultimately led to an increase in productivity. Nutraceuticals have recently attracted a lot of attention to alleviate the adverse impacts of heat stress in rabbit farms. The objective of the current review is to provide acquaintance with the recent findings about the impact of heat stress on rabbit productivity and the advantages of dietary supplementation of nutraceuticals in mitigating it.

Aspergillus awamori attenuates ochratoxin A-induced renal and cardiac injuries in rabbits by activating the Nrf2/HO-1 signaling pathway and downregulating IL1β, TNFα, and iNOS gene expressions

Ochratoxin A (OTA) is one of the most dangerous and that pollute agricultural products, inducing a variety of toxic effects in humans and animals. The current study explored the protective effect of different concentrations of Aspergillus awamori (A. awamori) against OTA (0.3 mg/kg diet) induced renal and cardiac damage by exploring its mechanism of action in 60 New Zealand white male rabbits. Dietary supplementation of A. awamori at the selected doses of 50, 100, and 150 mg/kg diet, respectively, for 2 months significantly improved the rabbit's growth performance; modulated the suppressed immune response and restored the altered hematological parameters; reduced the elevated levels of renal injury biomarkers such as urea, creatinine, and alkaline phosphatase; and increased serum total proteins concentrations. Moreover, it also declined enzymatic activities of cardiac injury biomarkers, including AST, LDH, and CK-MB. A. awamori alleviated OTA-induced degenerative and necrotic changes in the kidney and heart of rabbits. Interestingly, A. awamori upregulated Nrf2/OH-1 signaling pathway. Therefore enhanced TAC, CAT, and SOD enzyme activities and reduced OTA-induced oxidative and nitrosative stress by declining iNOS gene expression and consequently lowered MDA and NO levels. In addition to attenuating renal and cardiac inflammation via reducing IL-1β, TNF-α gene expressions in a dose-dependent response. In conclusion,this is the first report to pinpoint that dietary incorporation of A. awamori counteracted OTA-induced renal and cardiac damage by potentiating the rabbit's antioxidant defense system through its potent antioxidant, free radical scavenging, and anti-inflammatory properties in a dose-dependent response. Based on our observations, A. awamori could be utilized as a natural protective agent against ochratoxicosis in rabbits.

Ginger root powder enhanced the growth productivity, digestibility, and antioxidative capacity to cope with the impacts of heat stress in rabbits

Heat stress is the most significant environmental factor involved in the impairment of the health status of rabbits and lowering their productivity. Using medicinal feed additives is suggested to relieve heat stress-induced oxidative stress in rabbits. The study investigated the possible protective role of ginger root (Zingiber officinale) against heat stress in rabbits. Five week old rabbits were assigned randomly into four groups (48 rabbits each) and fed a basal diet supplemented with 0, 2.5, 5.0, and 7.5 g ginger powder/kg diet. The temperature and relative humidity inside the rabbitry units were kept at 33.0 ± 5.5 °C and 74.5 ± 4.5%, respectively, during 8 weeks fattening period. The results showed that rabbits that received the 7.5 g ginger powder/kg supplement had the highest final body weight. Rabbits that received different ginger powder levels recorded lower mortality values during the experimental period compared to that received the control diet, but the differences were not significant (5.0 vs. 10.0%, respectively). Rabbits fed 5.0 and 7.5 g ginger diet recorded the best food conversion ratio (P < 0.001). The weight of the carcass was significantly increased (P < 0.01) by supplementing ginger powder in diets. The digestibility of dry matter, organic matter, crude protein, and nitrogen free extracts nutrients was increased, but ether extract was significantly decreased (P < 0.001) by using ginger powder in diets. The detected blood metabolites displayed increased total protein but decreased triglycerides, total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) in rabbits treated with ginger. Rabbits fed 5.0 and 7.5 g ginger powder had the highest plasma total antioxidative capacity (TAC) and the lowest (P < 0.01) plasma malondialdehyde (MDA) concentration compared to those fed control diet. Conclusively, supplementing ginger powder up to a 5.0 g/kg diet for growing rabbits is recommended to improve the growth performance and enhanced viability under heat stress conditions.

The Influence of Chicken Egg Lysozyme or Zinc-Bacitracin Antibiotic on the Growth Performance, Antibacterial Capacity, Blood Profiles, and Antioxidative Status of Rabbits: A Comparative Study

Simple Summary

Despite the beneficial role of antibiotics in reducing bacterial infection in rabbits, there is an indirect harmful influence on human health. Thus, replacing antibiotics with friendly alternatives is a suitable strategy to protect the performance and welfare of rabbits. This study aimed at comparing the effects of including dietary egg lysozyme and zinc bacitracin antibiotic (ZnB) on the productivity and health conditions of rabbits. The results show a marked enhancement of the growth performance, antibacterial capacity, blood health, and antioxidative status in rabbits treated with egg lysozyme compared with those treated with ZnB. Thus, using egg lysozyme is recommended to replace the usage of ZnB in rabbit production.

Abstract

Dietary egg lysozyme has beneficial roles in the growth performance and health conditions of animals. The study was performed using 90 multicolored rabbits in three groups (each replicate with thirty rabbits). In the control group, rabbits were fed a diet without zinc bacitracin (ZnB) or egg lysozyme, while the second and third groups were treated with ZnB and lysozyme additive at 100 mg/kg, respectively. After eight weeks, the final weight and body weight gain (BWG) of rabbits fed dietary egg lysozyme and ZnB additives were meaningfully increased (p < 0.05). Nevertheless, the feed conversion ratio (FCR) was markedly decreased by dietary egg lysozyme and ZnB (p < 0.05). Interestingly, dietary egg lysozyme resulted in higher final weight and BWG and lower FCR than rabbits treated with ZnB (p < 0.05). Rabbits treated with egg lysozyme and ZnB additives had markedly lower populations of Clostridium spp. and Escherichia coli (p < 0.05) compared with the control. However, the counts of Lactobacillus and total bacteria were meaningfully increased in the the intestines of rabbits treated with egg lysozyme and ZnB (p < 0.05). The blood total protein and globulin of rabbits fed dietary egg lysozyme and ZnB additives were meaningfully increased (p < 0.05). Blood creatinine was significantly lowered by dietary egg lysozyme compared with the control and ZnB-treated rabbits (p < 0.05). The levels of blood urea, ALT, and AST were markedly lowered (p < 0.05) by dietary egg lysozyme and ZnB. The gene expressions of superoxide dismutase 1 (SOD1) and glutathione peroxidase (GPX) in the liver of rabbits fed dietary egg lysozyme and ZnB additives were markedly upregulated (p < 0.05) compared with the control. Dietary egg lysozyme resulted in higher expression of SOD1 and GPX genes than rabbits treated with ZnB (p < 0.05). In conclusion, the inclusion of egg lysozyme could replace the inclusion of ZnB in the diets of rabbits.

Aspergillus awamori positively impacts the growth performance, nutrient digestibility, antioxidative activity and immune responses of growing rabbits

In this study, we explored the effects of dietary administration of Aspergillus awamori on the growth, intestinal histomorphology, immune parameters and antioxidant enzyme activity of growing rabbits. The rabbits of 5 weeks of age (body weight, 855 ± 5.53 g) were allotted into four groups (12 rabbits per group) and fed four experimental diets enriched with A. awamori at 0, 50, 100 and 150 mg per kg diet for 8 weeks. After the feeding trial, an equal number of male APRI rabbits (3 months old; 4 groups, 5 rabbits per group) were housed in metabolism cages and fed the test diets for 14 days for the digestibility trial. All A. awamori-enriched diets induced a significant increase in the average body weight and weight gain of rabbits and significantly decreased the feed conversion ratio. In rabbits fed with A. awamori at 100 or 150 mg per kg diet, protein, lipid and fibber digestibility coefficients significantly increased compared with the control group. Intestinal villi measurements (length and thickness) were also enhanced in all rabbits fed with A. awamori. Adding A. awamori as a food supplement generally did not affect rabbit haematology and blood biochemistry values; however, at 150 mg per kg diet, it significantly increased the levels of haemoglobin and total protein, as well as red blood cell count. Furthermore, all enriched diets significantly increased rabbits' phagocytic activity and their phagocytic index. Rabbits fed with A. awamori also showed decreased malondialdehyde but increased catalase activity. In conclusion, A. awamori administered as feed supplement at 100-150 mg per kg of growing rabbits' diet enhances their growth, intestinal health and nutrient digestibility, and it raises the levels of their immune and antioxidative responses.