Impacts of supplementing growing rabbit diets with whey powder and citric acid on growth performance, nutrient digestibility, meat and bone analysis, and gut health

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.

Feeds of animal origin in rabbit nutrition – a review

Rabbits are classified as obligate herbivores. However, under natural conditions, some members of the family Leporidae incorporate animal products into their diets. Therefore, it seems biologically justified to supplement the diets of farmed rabbits with feeds of animal origin as sources of protein, fat and minerals. The aim of this review was to describe, from a historical perspective, the use of various feeds of animal origin in rabbit nutrition. The applicability of by-products from mammal, poultry, fish and invertebrate processing for rabbit feeding was evaluated, including the future prospects for their use. A review of the available literature revealed that various animal-based feeds can be valuable protein sources in rabbit diets, but their inclusion levels should not exceed 5-10%. Studies investigating their efficacy have been conducted since the 1970s. In some regions of the world, the use of animal-derived protein in livestock feeds was prohibited due to the risk of spreading bovine spongiform encephalopathy (BSE). However, the interest in animal by-products as protein sources in livestock diets is likely to increase since the above ban has been lifted.

Impact of Fennel Essential Oil as an Antibiotic Alternative in Rabbit Diet on Antioxidant Enzymes Levels, Growth Performance, and Meat Quality

In the current study, fennel essential oil was used as an antibiotic alternative compared to gentamycin for enhancing the expression of apoptosis genes and antioxidant enzymes in weaned rabbits as well as meat quality and growth performance. The gene expression of the cell lymphoma 2 (BAX and BCL2), caspase3 (CASP3), and glutathione peroxidase (GPX1) were estimated in the liver tissue using qRT-PCR. A total of 45 Moshtohor weaned male rabbits aged four weeks were randomly allocated to control, T1, and T2 treatment groups; each consisted of 15 weaned male rabbits with five replicates. Rabbits in the T1 and T2 groups were orally supplied with 1 mL fennel oil and 1 mL gentamycin, respectively. Weaned rabbits under different treatments showed increased body weight (BW) at 8 and 12 weeks of age and average daily gain (ADG) at 4-8 and 4-12 weeks of age compared to the control group. Compared to the controls, the weaned rabbits supplemented with fennel oil and gentamycin had lower total cholesterol, triglyceride, and MDA. In addition, villus length, mRNA of BAX, BCL2, Casp3, and GPX were increased in the different treatments compared to the control. Furthermore, the meat of these rabbits was less tender, had a lower aerobic plate count (APC), pH, and was brighter and redder in color than the control. Under the conditions of the present study, the supplementation of weaned Moshtohor rabbits with fennel oil as a natural alternative for gentamycin enhanced feed conversion and daily gain through enhancing villus length and mucus thickness. Additionally, fennel essential oil reduces oxidative stress by increasing the antioxidant enzymes.

Physiological Performance of Rabbits Administered Buffalo Milk Yogurts Enriched with Whey Protein Concentrate, Calcium Caseinate or Spirulina platensis

The present study examines the impacts of supplementing yogurt with 1% whey protein concentrate (WPC), Ca-caseinate (Ca-CN) and Spirulina platensis on the physiological performance of V-line rabbits receiving diets containing yogurt (at a dose of 5 g/kg body weight/day) and the different meat quality aspects. The results show that fat content was highest (p < 0.05) in yogurt fortified with Spirulina powder, but protein (%) was highest in yogurt enriched with WPC. Yogurt containing Spirulina powder showed a significant (p < 0.05) increase in total antioxidant activity. The final live body weight for G1 was higher than the other groups. However, additives affected the saddle, hind legs, liver and neck percentages significantly (p < 0.05). There were not significant differences for all groups in the forelegs, lung and heart percentages. LDL-cholesterol, total protein, globulin, albumin, creatinine and immunoglobulin M values were lowest (p < 0.05) in the WPC group. Significant improvements appeared in the small intestinal wall, microbiology, growth performance, serum biochemistry, organ histology and meat quality of the group receiving enriched yogurt. Yogurts enriched with WPC, Ca-CN and Spirulina platensis can be used as functional foods.

Nutritional, antimicrobial and medicinal properties of Camel's milk: A review

Camel's milk is an important part of staple diet in several parts of the world, particularly in the arid and semi-arid zones. Camel's milk is rich in health-beneficial substances, such as bioactive peptides, lactoferrin, zinc, and mono and polyunsaturated fatty acids. These substances could help in the treatment of some important human diseases like tuberculosis, asthma, gastrointestinal diseases, and jaundice. Camel's milk composition is more variable compared to cow's milk. The effects of feed, breed, age, and lactation stage on milk composition are more significant in camel. Region and season significantly change the ratio of compounds in camel's milk. Camel's whey protein is not only composed of numerous soluble proteins, but also has indigenous proteases such as chymotrypsin A and cathepsin D. In addition to their high nutritional value, these whey proteins have unique characteristics, including physical, chemical, physiological, functional, and technological features that are useful in the food application. The hydrolysis of camel's milk proteins leads to the formation of bioactive peptides, which affect major organ systems of the body and impart physiological functions to these systems. The camel's milk has antioxidant, antimicrobial, angiotensin-I-converting enzyme (ACE)-inhibitory peptides, antidiabetic as well as anticholesterol activities.

Growth performance, tissue precipitation, metallothionein and cytokine transcript expression and economics in response to different dietary zinc sources in growing rabbits

The impact of different dietary zinc sources on the growth, serum metabolites, tissue zinc content, economics and relative expression of cytokine and metallothionein genes was evaluated in this study. A total of 120 35-day-old male New Zealand White (NZW) rabbits were randomly distributed into four dietary experimental groups with 10 replicates per group and 3 animals per replicate. The control group was fed basal diet with a Zn-free vitamin-mineral premix; the other three groups received control basal diet supplemented with 50 mg/kg level with zinc oxide (ZnO; as inorganic source), Zn-methionine (Zn-Met; as organic source) and zinc oxide nanoparticles (nano-ZnO). The results indicated that Zn-Met and nano-ZnO groups significantly improved body weight, daily weight gain (DWG), feed conversion ratio (FCR) and nutrient digestibility, as well as decreased mortality, compared to ZnO and control groups. Zn-Met and nano-ZnO significantly reduced serum total cholesterol but did not affect serum proteins and liver function. Nano-ZnO supplemented group also recorded the highest value of serum alkaline phosphatase (ALP), insulin-like growth factor (IGF-1) and lysozymes compared to other groups. Nano-ZnO supplementation had increased hepatic Zn and Cu content and decreased faecal Zn content. Also nano-ZnO group recorded higher expression levels of genes encoding for metallothionein I and metallothionein II, interleukin-2 and interferon-γ in the liver of rabbits. The findings of this study demonstrated zinc nanoparticles, and organic zinc supplementation had improved growth performance and health status of growing rabbits than inorganic zinc oxide.

Dietary Supplementation of Carob and Whey Modulates Gut Morphology, Hemato-Biochemical Indices, and Antioxidant Biomarkers in Rabbits

This study aimed to evaluate the influence of the carob powder (CP) and sweet whey powder (WhP) inclusion into weaning feed on the gut morphology, hemato-biochemical parameters, and antioxidant biomarkers. The addition of 10 g/kg (basal diet +10 g/kg of CP, of WhP) or the mixture (5 g/kg of CP and 5 g/kg of WhP) in the rabbit's standard diet was assessed. A total of 40 weaned New Zealand White rabbits (4 weeks old) was distributed according to body weight (BW) into four treatments (n = 10) and the feed additives were provided for 7 weeks. Tissue samples and blood were obtained after slaughter. Final BW, daily weight gain, feed conversion ratio, intestinal morphology, and carcass dressing were positively affected by CP-WhP treatments compared with the control diet. Also, CP-WhP treatments significantly increased total proteins, calcium and iron levels, fecal cholesterol excretion, total antioxidants capacity, superoxide dismutase, and catalase in different tissues and significantly decreased total cholesterol, triglycerides, and glucose in blood serum. These changes were associated with a diminution of blood tumor necrosis factor alpha, lipid peroxidation, and carbonyl proteins in rabbit tissues. Both the additives separately and especially in the mix may enhance productive performance, protein profile, gut function, immunity, and antioxidant activity, with reducing lipid peroxidation, essential inflammatory mediator, and protein-carbonyl residues of growing rabbits. These findings suggest that CP-WhP dietary supplementation provides novel insights into a variety of bioactive compound mixtures with different beneficial modes of actions.

Effects of Phenolic-Rich Onion (Allium cepa L.) Extract on the Growth Performance, Behavior, Intestinal Histology, Amino Acid Digestibility, Antioxidant Activity, and the Immune Status of Broiler Chickens

The effect of phenolic-rich onion extract (PROE), as a feed additive, was evaluated on the growth, carcass traits, behavior, welfare, intestinal histology, amino acid ileal digestibility "AID%," and the immune status of broiler chicks for 35 days. A total number of 400, 1-day-old broiler chicks (45.38 g ± 1.35) were allocated to four different treatments with 10 replicates each (100 chicks/treatment) consisting of: T1, basal diet without additives (control treatment) (PROE0); T2, basal diet + phenolic-rich onion extract (1 g/kg diet) (PROE1); T3, basal diet + phenolic-rich onion extract (2 g/kg diet) (PROE2); and T4, basal diet + phenolic-rich onion extract (3 g/kg diet) (PROE3). An increase in the final body weight "FBW," bodyweight gain "BWG," and feed consumption was observed (P < 0.05) at different PROE levels. Also, the thymus and bursa percentages were increased in the PROE2 and PROE3 treatments (P < 0.05). The chicks fed on PROE supplemented diets had increased frequency of feeding and drinking and showed comfortable behavior (P < 0.05) with lesser aggression (P < 0.05). Additionally, an increase was observed in the antioxidant enzyme activity, phagocytic %, phagocytic index, and serum lysozyme activity in PROE supplemented treatments, with the best outcome reported in the PROE3 treatment (P < 0.01). IgM was increased in the birds fed with PROE2 and PROE3 diets (P < 0.01). PROE supplementation increased the AID% of lysine and methionine (P <0.01), PROE3 treatment increased the AID% of threonine (P < 0.05), and PROE2 and PROE3 treatments increased the AID% of leucine and isoleucine (P < 0.05). Besides, PROE2, and PROE3 treatments increased the villus height and width, mucosal thickness, and goblet cell count from the duodena, jejuna, and ilea (P < 0.05) compared to control treatment. Based on these results, we concluded that the dietary addition of phenolic-rich onion extracts can improve the growth rate of broiler chicken by improving the AID% of amino acids and intestinal histology. Also, it can improve the welfare, antioxidant enzymes activity, and immune status of the birds. Phenolic-rich onion extracts can be used as a natural growth promoter in the poultry feed for good health and improved performance.

Detoxification Impacts of Ascorbic Acid and Clay on Laying Japanese Quail Fed Diets Polluted by Various Levels of Cadmium

Simple Summary

The present study aimed to evaluate the impacts of ascorbic acid and clay supplementation on laying Japanese quail fed diets polluted by various levels of cadmium (Cd). Results revealed that consuming polluted diets with Cd causes harmful impacts on the productive performance of laying Japanese quail. The supplementation of ascorbic acid or natural clay to layer diets had beneficial effects on productive performance, improved egg quality and diminished the toxic effect of Cd.

Abstract

A total number of 360 laying Japanese quail (8 weeks of age) were randomly divided into 12 groups. Birds in all groups had nearly the same average initial body weight. A factorial arrangement (4 × 3) was performed including four levels of dietary cadmium (Cd) as cadmium chloride (0, 50, 100, and 150 mg/kg diet) and three levels of feed additives (without, 300 mg/kg ascorbic acid and 1.50% natural clay). Results revealed that Cd contaminated feed caused significant (p < 0.01) retardation in body weight, lower egg number and egg mass and worse feed conversion. On the other hand, the addition of ascorbic acid or natural clay to quail diets caused a significant (p < 0.01) improvement in all studied traits. With respect to the interaction among Cd and the experimental additives, results showed that within each Cd level, ascorbic acid or clay supplementation recorded the highest body weight, egg number, egg weight and mass in addition to improved feed conversion. Cadmium levels decreased (p < 0.05) blood total protein, albumen and A/G ratio. Both 300 mg ascorbic acid and 1.50% clay increased (p < 0.05) blood total protein and albumen compared to non-supplemented groups. It could be concluded that the consumption of polluted diets Cd causes deleterious effects on the productive performance of laying Japanese quail. The addition of ascorbic acid or natural clay to the diets causes beneficial effects on productive performance traits, improves egg quality criteria and diminishes the toxic effects of Cd.

The Effect of Dietary Replacement of Fish Meal with Whey Protein Concentrate on the Growth Performance, Fish Health, and Immune Status of Nile Tilapia Fingerlings, Oreochromis niloticus

Simple Summary

Although fish meal is considered the main animal protein source in fish diets, its high cost and unavailability limit its use in aquafeed. Recently, the search for other high-quality replacers of fish meal in aquatic feeds is being carried out with increased attentiveness. However, very few investigations have been performed to assess the possible use of whey protein concentrates (WPC) in Nile tilapia feeds. Five replacement percentages of fish meal with WPC (0%, 13.8%, 27.7%, 41.6%, and 55.5%) were assessed. WPC could replace the fish meal in Nile tilapia diets up to 27.7%, with improving the gut health, the total weight of survival fish, and immune status of fish challenged with Aeromonas hydrophila. High inclusion levels of WPC are not recommended in fish diets, since they negatively affected the intestinal and liver tissues and increased the level of cellular apoptosis, as indicated by the increased caspase 3 activity.

Abstract

The present study was conducted to assess the effect of replacing fish meal with whey protein concentrate (WPC) on the growth performance, histopathological condition of organs, economic efficiency, disease resistance to intraperitoneal inoculation of Aeromonas hydrophila, and the immune response of Oreochromis niloticus. The toxicity of WPC was tested by measuring the activity of caspase 3 as an indicator of cellular apoptosis. Oreochromis niloticus fingerlings with average initial weight 18.65 ± 0.05 gm/fish (n = 225) for a 10-week feeding trial. The fish were randomly allocated to five experimental groups, having five replacement percentages of fish meal with WPC: 0%, 13.8%, 27.7%, 41.6%, and 55.5% (WPC0, WPC13.8, WPC27.7, WPC41.6, and WPC55.5); zero percentage represented the control group. The results show that the fish fed WPC had the same growth performance as the WPC0. The total weight of bacterially challenged surviving fish increased linearly and quadratically (p ≤ 0.05) by increasing the replacement percentage of fish meal with WPC. The growth hormone, nitric oxide, IgM, complement 3, and lysozyme activity were seen to increase significantly in WPC27.7, especially after a bacterial challenge. The phagocytic percentage and phagocytic index increased significantly in WPC27.7, WPC41.6, and WPC55.5 groups. Histopathological examination of liver sections was badly affected by high replacement in WPC41.6–55.5. The activity of caspase 3 in the immunohistochemical stained sections of the intestine was increased significantly by increasing the inclusion level of WPC. Economically, the total return of the total surviving fish after the bacterial challenge was increased significantly by fish meal replacement with WPC. It could be concluded that WPC could replace the fish meal in Nile tilapia diets up to 27.7%, with improving the gut health, the total weight of survival fish, and immune status of fish challenged with A. hydrophila. High inclusion levels of WPC are not recommended in fish diets, since they negatively affected the intestinal and liver tissues and increased the level of cellular apoptosis, as indicated by the increased caspase 3 activity. Further researches are recommended to evaluate the effect of fish meal replacement with WPC on the histopathological examination of the kidney and to test the capacity of serum IgM to clot the bacteria used for the challenge.

The Effect of Substitution of Palm Fat with Linseed Oil on the Lipid Peroxidation, Antioxidative Capacity and Intestinal Morphology in Rabbits (Oryctolagus cuniculus)

Simple Summary

By changing the source of fat in the diet of animals, the fat content of animal products, such as meat, could be improved. The addition of linseed oil, with a high proportion of polyunsaturated fatty acids, especially n-3 α-linolenic acid, is often used in animal nutrition. Rabbit diet manipulation is effective in increasing or changing the level of fatty acids such that meat could become a functional food for humans. Since polyunsaturated fatty acids are susceptible on oxidation, an effect on animal health could arise. Therefore, we conducted a trial replacing palm fat (saturated fatty acids) with linseed oil (polyunsaturated fatty acids) in the rabbit diet to compere the oxidative status and histology of intestinal tissues. There was no significant effect in the substitution of linseed oil on the malondialdehyde concentration in urine and plasma, antioxidative capacity of water soluble or lipid soluble antioxidants, or intestinal morphology. Therefore, with an appropriate dietary strategy, the content of rabbit meat can be improved without reducing animal welfare.

Abstract

This experiment was conducted to investigate the effect of different dietary fatty acids (saturated or polyunsaturated fatty acids) supplementation on the oxidative status and intestinal morphology of adult rabbits (Oryctolagus cuniculus). Twenty-four “slovenska kunka” rabbits were randomly assigned to two different dietary treatments (12 rabbits per treatment) and fed the experimental diets between 80 and 102 days of age. The palm fat (PALM) diet with 6% palm fat and linseed (LINSEED) diets with 6% linseed oil were used. To evaluate the oxidative status of rabbits, the malondialdehyde concentration in urine and plasma and concentration of water and lipid soluble antioxidants in plasma were measured. The antioxidative capacity of the gastrointestinal tract was evaluated by measuring concentration of water and lipid soluble antioxidants in tissues and contents of the intestine. The histological structure of the small intestine and caecum was analyzed via histomorphometric analysis. No significant differences were found in either of those parameters. In summary, rabbits were exposed to high levels of polyunsaturated fatty acids with a high predisposition to oxidation, but their health and welfare were not endangered.