پردیس کشاورزی و منابع طبیعی دانشگاه تهران Iranian Journal of animal Science 2008-4773 56 3 2025 09 23 Investigating the effect of cottonseed bioactive peptides and organic zinc supplementation in the close-up diet on the immune status, blood metabolites and milk production of Holstein fresh cows Investigating the effect of cottonseed bioactive peptides and organic zinc supplementation in the close-up diet on the immune status, blood metabolites and milk production of Holstein fresh cows 627 648 101790 10.22059/ijas.2025.391319.654067 FA Zahra Hosseini Firozkohi PhD. Candidate, Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan Hamid Amanlou Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Fateme Ahmadi Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Yasaman Amanlou Biosystem Engineering Department , Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. Hojat Mazaheri talise nemone dairy farm 0009-0003-5382-9963 Journal Article 2025 03 10 The aim of this research was to investigate the effects of cottonseed bioactive peptides and organic zinc supplementation in the prepartum diet on the immune response and milk production of Holstein fresh cows. A total of one hundred and eighty multiparous Holstein cows were divided into four experimental groups: 1) Basal diet (containing mineral zinc recommended in NRC (2001)) without Pe0Zn0 peptide; 2) Basal diet (containing mineral zinc recommended in NRC (2001)) with 300 g of bioactive peptide Pe1Zn0; 3) Basal diet (containing mineral zinc recommended in NRC (2001)) with 160 mg organic zinc per kg dry matter and without bioactive peptides Pe0Zn1 and 4) Basal diet (containing mineral zinc recommended in NRC (2001)) with 160 mg organic zinc per kg dry matter and 300 g bioactive peptide Pe1Zn1. Samples were collected from cows at various time points before and after calving, with milk production monitored daily from 1 to 21 days post-calving. Data analysis was carried out using SAS (2010) software in a completely randomized design. The results indicated that including peptides in the prepartum diets led to increased serum levels of calcium, albumin, total antioxidant capacity, and creatinine kinase while glucose levels decreased in the prepartum period (P < 0.05).  Similarly, higher organic zinc levels in the prepartum diet resulted in elevated concentrations of calcium, antioxidant capacity, aspartate aminotransferase, and insulin, while glucose and malondialdehyde levels decreased (P < 0.05). The inclusion of peptides in the prepartum diets led to a notable increase in total antioxidant capacity and glutathione peroxidase concentrations, while simultaneously reducing insulin and Tendency to decrease glucose levels in the postpartum period (P < 0.01). Additionally, the introduction of organic zinc into the diets resulted in elevated levels of phosphorus, cholesterol, aspartate aminotransferase, total antioxidant capacity, along with decreased serum bilirubin concentrations postpartum (P < 0.01). The serum phosphorus levels postpartum were significantly influenced by both organic zinc and peptide supplementation (P = 0.01). Furthermore, the addition of cottonseed bioactive peptides (P = 0.06) and organic zinc (P < 0.01) to the experimental diet led to a substantial increase in milk production. Specifically, the incorporation of organic zinc into the prepartum diet resulted in a significant rise in milk fat, protein and lactose percent and milk solids content among fresh cows (P < 0.01). Overall, the supplementation of cottonseed bioactive peptides and organic zinc in the prepartum diets of cows proved to enhance the immune status and production of fresh cows. The aim of this research was to investigate the effects of cottonseed bioactive peptides and organic zinc supplementation in the prepartum diet on the immune response and milk production of Holstein fresh cows. A total of one hundred and eighty multiparous Holstein cows were divided into four experimental groups: 1) Basal diet (containing mineral zinc recommended in NRC (2001)) without Pe0Zn0 peptide; 2) Basal diet (containing mineral zinc recommended in NRC (2001)) with 300 g of bioactive peptide Pe1Zn0; 3) Basal diet (containing mineral zinc recommended in NRC (2001)) with 160 mg organic zinc per kg dry matter and without bioactive peptides Pe0Zn1 and 4) Basal diet (containing mineral zinc recommended in NRC (2001)) with 160 mg organic zinc per kg dry matter and 300 g bioactive peptide Pe1Zn1. Samples were collected from cows at various time points before and after calving, with milk production monitored daily from 1 to 21 days post-calving. Data analysis was carried out using SAS (2010) software in a completely randomized design. The results indicated that including peptides in the prepartum diets led to increased serum levels of calcium, albumin, total antioxidant capacity, and creatinine kinase while glucose levels decreased in the prepartum period (P < 0.05).  Similarly, higher organic zinc levels in the prepartum diet resulted in elevated concentrations of calcium, antioxidant capacity, aspartate aminotransferase, and insulin, while glucose and malondialdehyde levels decreased (P < 0.05). The inclusion of peptides in the prepartum diets led to a notable increase in total antioxidant capacity and glutathione peroxidase concentrations, while simultaneously reducing insulin and Tendency to decrease glucose levels in the postpartum period (P < 0.01). Additionally, the introduction of organic zinc into the diets resulted in elevated levels of phosphorus, cholesterol, aspartate aminotransferase, total antioxidant capacity, along with decreased serum bilirubin concentrations postpartum (P < 0.01). The serum phosphorus levels postpartum were significantly influenced by both organic zinc and peptide supplementation (P = 0.01). Furthermore, the addition of cottonseed bioactive peptides (P = 0.06) and organic zinc (P < 0.01) to the experimental diet led to a substantial increase in milk production. Specifically, the incorporation of organic zinc into the prepartum diet resulted in a significant rise in milk fat, protein and lactose percent and milk solids content among fresh cows (P < 0.01). Overall, the supplementation of cottonseed bioactive peptides and organic zinc in the prepartum diets of cows proved to enhance the immune status and production of fresh cows. https://ijas.ut.ac.ir/article_101790_12380bec73bb6ad7ad293f323e1aa370.pdf