Monitoring the effects of oxidative stress on the growth of Holstein bull calves using diquat

Ting Liu ^1* Huan Chen ¹ DongZhu CaiRang ¹ ShuRu Cheng ^1,2 Zhihao Luo ¹ Ming Zhang ³ David Casper ^4,5

• ¹ College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu Province, China
• ² College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu Province, China
• ³ Gansu Devotion Biotech Co., Ltd, Lanzhou, Gansu, China, Lanzhou, China
• ⁴ Casper’s Calf Ranch, LLC, Freeport, IL, USA, Freeport, IL, United States
• ⁵ Laboratory of Developmental Nutrition, Department of Animal Science, North Carolina State University, Raleigh, North Carolina, United States

Background: Holstein bull calves were given a one-time intraperitoneal injection of Diquat to explore the effects of Diquat on growth , body frame, blood oxidation indices, and fecal scores and pathogenic bacteria in weaned calves.Methods: Twelve 70-d Holstein bull calves of similar body weight (BW) and body condition were randomly assigned to 1 of 4 treatments. Treatments were: Control: calves were injected with 0 mg/kg BW Diquat in 0.9 % sterilized saline; treatment: 6, 8 and 10 mg/kg BW; Diquat, respectively. The experimental period was 24 days. Measurements of BW, average daily gain (ADG), faecal scores, frame gains, fecal pathogen count, and blood samples for monitoring oxidative stress were collected at 0, 6, 12, 18 and 24 d. Data were analysed as a randomized complete block design with d as a repeated measurement. In addition, exponential polynomial contrasts were used to test the linear, quadratic, and cubic treatment responses.Results: Growth performance (BW), and ADG demonstrated a cubic response (P < 0.02) by decreasing then increasing with increasing Diquat dosage. Faecal scores and faecal ratios demonstrated a quadratic response (P < 0.02) by increasing at a decreasing rate with increasing Diquat injection dosage. Frame gains for body slope, body length, hip heights, and abdominal girth demonstrated a linear (P < 0.03) decrease with increasing Diquat injection dosage. Serum aspartate aminotransferase, glutathione, total antioxidant capacity, catalase, malondialdehyde, cortisol, and noradrenaline concentrations demonstrated a linear increase (P < 0.01) with increasing Diquat injection dosage, while alanine transaminase, superoxide oxide dismutase, and glutathione peroxidase demonstrated a quadratic response (P < 0.02) by increasing at a decreasing rate. Faecal Escherichia coli concentrations demonstrated a cubic response (P < 0.01), while Staphylococcus aureus and Salmonella-shigella demonstrated linear increases (P < 0.01) with increasing Diquat dosage.Conclusions: Diquat injection caused oxidative stress, resulting in reduced growth performance, with increasing indices of serum oxidative stress, faecal scores, and faecal pathogens, a response that can last for up to 24 days. 8 mg/kg BW being the optimal dosage as a target dosage for elucidating oxidative stress for evaluating future technologies to reduce, eliminate, or prevent oxidative stress.