Linneen Sara K, Arentson Roger A, Chewning J Jeffrey, Carr Scott N
Elanco Animal Health, Greenfield, IN 46140, USA.
Swine Research Services, Summers, AR 72769, USA.
Transl Anim Sci. 2021 Feb 8;5(1):txab020. doi: 10.1093/tas/txab020. eCollection 2021 Jan.
The objective of this experiment was to determine the effects of narasin (NAR; Skycis®; Elanco Animal Health, Greenfield, IN) or virginiamycin (VIR; Stafac®; Phibro Animal Health Corporation, Teaneck, NJ) on finishing pig growth performance and carcass characteristics. Two separate experiments were conducted at the same site in 2013 and 2014. A total of 576 pigs (initial BW = 23.2 ± 0.19 kg) were housed in 24 pens with 8 pigs per pen in Exp. 1. In Exp. 2, a total of 888 pigs (initial BW = 26.2 ± 0.12 kg) were housed in 39 pens with 8 pigs per pen. Treatments consisted of a series of unmedicated corn-soybean meal diets (CON), CON + NAR (15 mg/kg), or CON + VIR (11 mg/kg) fed for 108 d (Exp. 1) or 109 d (Exp. 2). Pen was the experimental unit in both studies. Data were analyzed as a randomized complete block design with the main effects of block and treatment (Exp. 1) and as an incomplete block design with the fixed effect of treatment and the random effects of barn and barn within block (Exp. 2). In Exp.1, NAR and VIR increased ( < 0.05) ADG and ADFI from days 0 to 28, and BW on days 28, 56, 76, and 97 as compared to pigs fed CON. During days 0-28, pigs fed NAR had a greater ( < 0.05) G:F than those fed CON or VIR. Also, during days 28-56 pigs fed VIR had a greater ( < 0.05) ADFI than pigs fed CON. Pigs fed NAR or VIR had greater ( < 0.05) carcass yield than those fed CON. In Exp.2, feeding NAR increased ( < 0.05) pig BW from days 54 through 96 compared to pigs fed CON or VIR. No differences ( > 0.05) in ADG were detected between pigs fed VIR and CON through the first 74 day, but ADG of pigs fed VIR was similar to ( > 0.05) those fed NAR from days 26 to 54. From day 0 to 109, NAR improved ADG compared to pigs fed VIR, which also had similar gain to those consuming CON ( = 0.04). Feed efficiency was similar between pigs fed NAR and VIR with pigs fed CON intermediate ( = 0.05). Pigs fed NAR had a greater ( < 0.05) HCW and loin depth than those fed CON or VIR. A subtherapeutic dose of VIR showed improvements in growth performance that were similar to NAR in one experiment. Although there were differences in the magnitude of growth and carcass effects of NAR between the two studies, pigs fed NAR showed at least a tendency to have greater G:F and in some cases increased carcass weight and yield compared to pigs consuming nonmedicated feed.
本实验的目的是确定那拉菌素（NAR；速百治®；美国礼蓝动物保健品公司，格林菲尔德，印第安纳州）或维吉尼亚霉素（VIR；畜大壮®；菲布罗动物保健公司，蒂内克，新泽西州）对育肥猪生长性能和胴体特性的影响。2013年和2014年在同一地点进行了两项独立实验。实验1中，共有576头猪（初始体重=23.2±0.19千克）被饲养在24个猪栏中，每个猪栏8头猪。实验2中，共有888头猪（初始体重=26.2±0.12千克）被饲养在39个猪栏中，每个猪栏8头猪。处理方式包括一系列未添加药物的玉米-豆粕日粮（CON）、CON+NAR（15毫克/千克）或CON+VIR（11毫克/千克），饲喂108天（实验1）或109天（实验2）。两项研究中，猪栏均为实验单位。数据采用随机完全区组设计进行分析，实验1的主要效应为区组和处理，实验2采用不完全区组设计，处理为固定效应，畜舍和区组内畜舍为随机效应。在实验1中，与饲喂CON日粮的猪相比，NAR和VIR在第0至28天提高了（P<0.05）平均日增重（ADG）和平均日采食量（ADFI），并在第28、56、76和97天提高了体重。在第0至28天，饲喂NAR的猪的料重比（G:F）高于饲喂CON或VIR的猪（P<0.05）。此外，在第28至56天，饲喂VIR的猪的ADFI高于饲喂CON的猪（P<0.05）。饲喂NAR或VIR的猪的胴体产量高于饲喂CON的猪（P<0.05）。在实验2中，与饲喂CON或VIR的猪相比，饲喂NAR使猪在第54至96天的体重增加（P<0.05）。在前74天，饲喂VIR的猪与饲喂CON的猪之间未检测到ADG差异（P>0.05），但在第26至54天，饲喂VIR的猪的ADG与饲喂NAR的猪相似（P>0.05）。从第0至109天，与饲喂VIR的猪相比，NAR提高了ADG，饲喂VIR的猪的增重与饲喂CON的猪相似（P=0.04）。饲喂NAR和VIR的猪的饲料效率相似，饲喂CON的猪居中（P=0.05）。饲喂NAR的猪的热胴体重（HCW）和腰部厚度高于饲喂CON或VIR的猪（P<0.05）。在一项实验中，亚治疗剂量的VIR在生长性能方面的改善与NAR相似。尽管两项研究中NAR对生长和胴体的影响程度存在差异，但与采食未添加药物饲料的猪相比，饲喂NAR的猪至少有提高G:F的趋势，在某些情况下胴体重和产量增加。
