Health Aspects, Growth Performance, and Meat Quality of Rabbits Receiving Diets Supplemented with Lettuce Fertilized with Whey Protein Hydrolysate Substituting Nitrate

Abstract

Lettuce (Lactuca sativa) was grown using a foliar spray with whey protein hydrolysate (WPH) as opposed to normal nitrate fertilization. Lettuce juice was prepared from lettuce cultivated without any fertilization, nitrate fertilization, or WPH. Sixty weaned, 4-week-old male V-line rabbits with an average 455 ± 6 g body weight were randomly divided into 4 groups (n = 15) and administered different lettuce juices. Rabbits administered WPH-fertilized lettuce showed significantly higher (n = 5, p < 0.05) body weight and carcass weight than those receiving nitrate-fertilized lettuce. Rabbits administered nitrate-fertilized lettuce were associated with significantly (p < 0.05) higher levels of liver enzyme activities (AST, ALT, and ALP), bilirubin (total, direct, and indirect), and kidney biomarkers (creatinine, urea, and uric acid). Rabbits administered WPH-fertilized lettuce avoided such increases and exhibited normal levels of serum proteins. Rabbits administered nitrate-fertilized lettuce manifested significantly (p < 0.05) lower RBCs and Hb levels than that of the other groups, while those receiving WPH-fertilized lettuce showed the highest levels. Liver and kidney sections of rabbits receiving WPH-fertilized lettuce witnessed the absence of the histopathological changes induced by feeding on nitrate-fertilized lettuce and produced higher quality meat. WPH-lettuce can substitute nitrate-fertilized lettuce in feeding rabbits for better performance and health aspects.

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

“…These properties have also been widely reported for many other essential oils and their constituents [ 61 ]. The results reflecting the improved quality of rabbit meat obtained after feeding on the enriched diets are consistent with previous studies [ 36 , 62 ].…”

“…Additionally, moisture contents were assessed by AOAC methodology [ 34 ]. The keeping quality of the rabbit’s meat was evaluated over 10 days, as stated previously for chicken [ 35 ], and rabbit meat [ 36 ] where the hind legs were directly separated from the rabbit carcasses under sterilized condition, the bone was trimmed, the meat portions from various replicates of the same group were minced together, and then 25 g of the meat homogenate were loaded into a sterilized 50 mL falcon tube. Three falcon tubes were distributed for each checkpoint (5 checkpoints; day 1, day 3, day 5, day 7, and day 10) and placed in a programmable incubator (Binder KB 23, BINDER GmbH (Headquarters), Tuttlingen, Germany) at 5 ± 0.2 °C for further determination of aerobic plate count (APC) and pH.…”

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

“…This decrease in pH can be related to the acid production activity of the intestinal organisms, including lactic acid bacteria, which occur through fermenting lactose to lactic acid, and volatile fatty acids in the intestinal lumen [65]. The results reflecting the improved quality of rabbit meat obtained after feeding on the enriched diets are consistent with previous studies [19,[66][67][68], defining the Spirulina in the diet as the reason for increasing the ratio n-6/n-3 PUFA and CLA in the lipid content of muscle.…”

Enhancing Grain Yield and Nitrogen Accumulation in Wheat Plants Grown under a Mediterranean Arid Environment by Foliar Spray with Papain-Released Whey Peptides

“…The buffalo milk (Zagazig City, Egypt) was centrifuged (6000× g, 10 min) and the resulting skimmed milk was acidified to pH 4.6 to coagulate the caseins [22]. The whey protein hydrolysate (WPH) was obtained as stated by [35] by hydrolysis with papain (E/S ratio 1:2) for 3 h with 25% degree of hydrolysis.…”

“…Protein hydrolysates are mixtures of free amino acids and polypeptides resulting from chemical and enzymatic hydrolysis of agro-industrial protein by-products derived from plant or animal origins [19]. They are qualified as bio-stimulants capable of promoting plant growth, crop productivity, and alleviating environmental stress impact [20][21][22]. Protein hydrolysates may enhance nutrient uptake and N metabolism through the activation of enzymes involved in their metabolism, thus enhancing the use efficiencies of micro and macronutrients [23].…”