| 3 | Effect of supplementation with n-3 polyunsaturated fatty acids and/or β-glucans on performance, feeding behaviour and immune status of Holstein Friesian bull calves during the pre-and post-weaning periods显示文摘Background: Previous research in both calves and other species has suggested n-3 polyunsaturated fatty acids(PUFA) and β-glucans may have positive effects on immune function. This experiment measured performance,behaviour, metabolite and immunological responses to pre-weaning supplementation of dairy bull calves with n-3 PUFA in the form of fish oil and β-glucans derived from seaweed extract. 44 Holstein Friesian bull calves, aged 13.7± 2.5 d and weighing 48.0 ± 5.8 kg were artificially reared using an electronic feeding system. Each calf was offered5 L(120 g/L) per day of milk replacer(MR) and assigned to one of four treatments included in the MR,(1) Control(CON);(2) 40 g n-3 PUFA per day(FO);(3) 1 g β-glucans per day(GL) and(4) 40 g n-3 PUFA per day & 1 g/d β-glucans(FOGL) in a 2 × 2 factorial design. Milk replacer and concentrate was offered from d 0–62(pre-weaning),while concentrate provision continued for a further 31 d post-weaning period. Individual daily feed intake and feeding behaviour was recorded throughout, while bodyweight and blood analyte data were collected at regular intervals.Results: Overall mean concentrate DMI from d 0–93 was 1.39, 1.27, 1.00 and 0.72 kg/d for CON, FO, GL and FOGL calves, respectively(SEM = 0.037;P < 0.0001). Calves supplemented with GL were significantly lighter(P < 0.0001) at both weaning(d 62) and turnout to pasture(d 93) than un-supplemented calves, with a similar effect(P < 0.0001)evident for calves receiving FO compared to un-supplemented contemporaries. Supplementation with GL reduced the number of unrewarded visits where milk was not consumed(P < 0.0001) while supplementation with FO increased mean drinking speed(P < 0.0001). Supplementation with GL resulted in greater concentrations of haptoglobin(P = 0.034), greater serum osmolality(P = 0.021) and lower lymphocyte levels(P = 0.027). In addition,cells from GL supplemented calves exhibited a lower response than un-supplemented contemporaries to both Phytohaemagglutinin A stimulated IFN-γ(P = 0.019) and Concanavalin A stimulated IFN-γ(P = 0.012) following in vitro challenges.Conclusions: Pre-weaning supplementation of bull calves with either n-3 PUFA or β-glucan resulted in reduced voluntary feed intake of concentrate and consequently poorer pre-weaning calf performance. There was no evidence for any beneficial effect of either supplementation strategy on calves’ immune responses. | Ruairi P.McDonnell John V.O’Doherty Bernadette Earley Anne Marie Clarke David A.Kenny | 2019 | Journal of Animal Science and Biotechnology2019，10，2： | 1 |
您所在的机构暂未开通此部分的功能，请联系管理员