Effects of supplemental zinc sulfate on growth performance, carcass characteristics, and antimicrobial resistance in feedlot heifers

Impact of zinc supplementation on phenotypic antimicrobial resistance of fecal commensal bacteria from pre-weaned dairy calves

The objective of this study was to evaluate the impact of dietary zinc supplementation in pre-weaned dairy calves on the phenotypic antimicrobial resistance (AMR) of fecal commensal bacteria. A repository of fecal specimens from a random sample of calves block-randomized into placebo (n = 39) and zinc sulfate (n = 28) groups collected over a zinc supplementation clinical trial at the onset of calf diarrhea, calf diarrheal cure, and the last day of 14 cumulative days of zinc or placebo treatment were analyzed. Antimicrobial susceptibility testing was conducted for Enterococcus spp. (n = 167) and E. coli (n = 44), with one representative isolate of each commensal bacteria tested per sample. Parametric survival interval regression models were constructed to evaluate the association between zinc treatment and phenotypic AMR, with exponentiated accelerated failure time (AFT) coefficients adapted for MIC instead of time representing the degree of change in AMR (MIC Ratio, MR). Findings from our study indicated that zinc supplementation did not significantly alter the MIC in Enterococcus spp. for 13 drugs: gentamicin, vancomycin, ciprofloxacin, erythromycin, penicillin, nitrofurantoin, linezolid, quinupristin/dalfopristin, tylosin tartrate, streptomycin, daptomycin, chloramphenicol, and tigecycline (MR = 0.96-2.94, p > 0.05). In E. coli, zinc supplementation was not associated with resistance to azithromycin (MR = 0.80, p > 0.05) and ceftriaxone (MR = 0.95, p > 0.05). However, a significant reduction in E. coli MIC values was observed for ciprofloxacin (MR = 0.17, 95% CI 0.03-0.97) and nalidixic acid (MR = 0.28, 95% CI 0.15-0.53) for zinc-treated compared to placebo-treated calves. Alongside predictions of MIC values generated from these 17 AFT models, findings from this study corroborate the influence of age and antimicrobial exposure on phenotypic AMR.

Impact of zinc, copper, manganese and chromium supplementation on growth performance and blood metabolic profile of Sahiwal (Bos indicus) male calves

This study aimed to see the effect of oral supplementation of specific trace minerals mixture on the growth, immunity, and reproductive development of indigenous growing bull calves. Eighteen Sahiwal bull calves, with an average age of 6 months were chosen and divided into three groups. Group 1 was fed with a basal diet, Group 2 was provided with an additional specific trace mineral supplement to achieve a diet containing 70 ppm of Zn, 17.50 ppm of Cu, 65 ppm of Mn, and 1.75 ppm of Cr. Group 3 received a 25% extra supplement to achieve a diet containing 87.50 ppm of Zn, 21.87 ppm of Cu, 81.25 ppm of Mn, and 2.18 ppm of Cr. The experiment was carried out for a total of 180 days. According to the findings, there was no significant impact of specific trace minerals supplementation on the animals' body weight, morphometric parameters, dry matter intake, average daily gain, nutritional value, digestibility and nitrogen retention. However, higher levels of Zn, Cu, and Mn led to increased (p < 0.05) total retention, while Cr retention remained the same. Serum mineral concentrations of Zn, Cu, and Mn increased significantly (p < 0.05) in G2 and G3 compared to the G1 group while Ca, P, and Cr had no significant change. Blood plasma glucose, albumin, globulin, and total protein showed no significant differences. Plasma alkaline phosphatase activity improved significantly (p < 0.05) in G2 and G3 but alanine transaminase, aspartate aminotransferase, hemoglobin, hematocrit, and IGF-1 remained unchanged. Superoxide dismutase activity, ferric-reducing antioxidant power, and total immunoglobulin concentration increased significantly (p < 0.05) in G2 and G3 groups, however, catalase activity and IgG count did not change among the groups. Mineral-supplemented groups (G2 and G3) showed a significant change (p < 0.05) in testosterone production during the 120th and the 180th day of the trial. Scrotal circumference and temperature gradient of the scrotal surface did not show any significant change. Supplementing growing bull calves with specific trace minerals above the basal level (70, 17.50, 65 and 1.75 ppm of Zn, Cu, Mn and Cr) has no direct beneficial effect on the growth parameters but can have positive effects on their antioxidant status, immunity and reproductive development as the related blood parameters were positively affected.

Vitamins and Trace Minerals in Ruminants: Confinement Feedlot

Trace minerals and vitamins are essential for optimizing feedlot cattle growth, health, and carcass characteristics. Understanding factors that influence trace mineral and vitamin absorption and metabolism is important when formulating feedlot cattle diets. Current feedlot industry supplementation practices typically exceed published trace mineral requirements by a factor of 2 to 4. Therefore, the intent of this review is to briefly discuss the functions of trace minerals and vitamins that are typically supplemented in feedlot diets and to examine the impact of dose of trace mineral or vitamin on growth performance, health, and carcass characteristics of feedlot cattle.

The influence of dietary energy and zinc source and concentration on performance, trace mineral status, and gene expression of beef steers

The objective of this study was to determine the effects of increased supplemental Zn from differing sources on growth performance of steers fed diets differing in net energy. Angus steers (n = 72, 324 ± 2.1 kg) with Genemax gain scores of 3, 4, or 5 were blocked by BW and stratified by Genemax gain score into 12 pens of 6 steers each for 158 d. Pens were randomly assigned to 1 of 3 Zn treatments (ZNTRT): 1) control (no supplemental Zn, analyzed 33 mg Zn/kg DM; CON); 2) inorganic Zn (CON + 120 mg supplemental Zn/kg DM as ZnSO₄ for entire trial; INZN); or 3) 120 mg supplemental Zn/kg DM as Zn-amino acid complex (Availa-Zn; Zinpro, Eden Prairie, MN) for first 60 d, then a blend of ZnSO₄ and Zn-AA complex (CON + 60 mg supplemental Zn/kg DM as ZnSO₄ + 60 mg supplemental Zn/kg DM as Zn-amino acid complex) for the remainder of the trial (ZNBLD). Two dietary energy strategies (ENERGY) were formulated to reach ADG rates of 1) 1.6 kg/d (LE) or 2) 2.0 kg/d (HE) utilizing a 3 × 2 factorial arrangement (12 steers/treatment). All steers were fed LE for a 60 d growing period, then pens were randomly assigned to ENERGY treatments fed the remaining 91 d. Day 60 BW tended to be greater (P = 0.07) in steers receiving supplemental Zn vs. CON. Liver Cu was decreased in Zn supplemented steers vs. CON (P = 0.02). Liver Zn concentrations on d 56 did not differ for Zn vs. CON (P = 0.22) nor were there differences due to Zn source (P = 0.98). There were or tended to be ZNTRT × ENERGY effects for d 67-90 ADG and G:F (P ≤ 0.01), and d 122 BW and d 90-122 G:F (P ≤ 0.10) driven by improved performance for ZNBLD-HE over ZNBLD-LE, while ENERGY within CON and INZN did not differ. Day 90-122 ADG, overall ADG and overall G:F was greater (P ≤ 0.02) and d 67-90 G:F tended to be greater (P = 0.10) for HE vs. LE. No ZNTRT × ENERGY or ZNTRT effects were detected for HCW, REA, BF, KPH, MS, or YG (P ≥ 0.37) while HE increased HCW, BF, MS, and YG compared with LE (P ≤ 0.05). In the liver, ZNTRT affected d 97 MT1A expression (P = 0.03) where INZN was greater than ZNBLD or CON (P ≤ 0.02), while ZIP14 was unaffected due to ZNTRT, ENERGY, or the interaction (P ≥ 0.39). Supplying supplemental Zn as ZNBLD during the transition period appeared to improve performance measures, but no final performance advantages were noted due to increased supplemental Zn, regardless of source. Additionally, differences in liver MT1A expression may indicate differing post-absorptive metabolism between Zn sources.