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

• Main Authors: Ali Osman, Tharwat A. Imbabi, Abdalla El-Hadary, Islam Ibrahim Sabeq, Shimaa N. Edris, Abdel-Rahaman Merwad, Ehab Azab, Adil A. Gobouri, Amaal Mohammadein, Mahmoud Sitohy
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Biomolecules
• Subjects: lettuce; nitrogen fertilization; whey protein hydrolysates; rabbits; growth performance; meat quality
• Online Access: https://www.mdpi.com/2218-273X/11/6/835

Lettuce (<i>Lactuca sativa</i>) 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 (<i>n</i> = 15) and administered different lettuce juices. Rabbits administered WPH-fertilized lettuce showed significantly higher (<i>n</i> = 5, <i>p</i> < 0.05) body weight and carcass weight than those receiving nitrate-fertilized lettuce. Rabbits administered nitrate-fertilized lettuce were associated with significantly (<i>p</i> < 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 (<i>p</i> < 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.