减缓育肥猪生长速度的营养措施:在胴体组成和猪肉质量方面的应用

发布单位:天津瑞孚农牧科技集团有限公司

查看次数:6154

时间:2021-01-21
      尽管养猪业主要目的在于提高生长速度,但是偶尔也会减缓育肥猪生长速度,比如当屠宰工厂产能受限时。有多种日粮措施可以降低育肥猪生长速度,这样当屠宰厂产能恢复时猪也处于最佳体重。但是这些措施对猪胴体质量大部分指标的影响仍未知。因此,本试验的目的在于评估育肥末期减缓生长速度的日粮措施的有效性,并评估其对胴体组成和猪肉质量的影响。
      试验选用897头猪(125±2kg,公母混群),随机分至48个圈,并接受6个日粮处理,每个处理8圈。试验日粮包括:对照组(典型育肥期日粮);氯化钙组(日粮中添加3%氯化钙);玉米组(日粮中无豆粕,玉米含量97%);异亮氨酸缺乏组;15%中性洗涤纤维组(NDF,日粮中添加豆皮,NDF含量15%);20%NDF组(日粮中添加豆皮,NDF含量20%)。试验期42天,每圈记录体重和饲料采食量。在试验第14、28、42天分三批屠宰,收集胴体数据。每批屠宰的猪中,每个处理收集20头猪的里脊肉(总120头),分析猪肉质量指标。
      全期来看,氯化钙组、玉米组、20%NDF组猪的生长速度较对照组有显著下降(P<0.001)。但是只有氯化钙组和20%NDF组的采食量显著降低(P<0.001)。氯化钙和玉米组饲料效率显著下降(P<0.001)。氯化钙组第14、28、42天胴体重都显著降低,玉米组、20%NDF组在第28、42天屠宰时的胴体重也比对照组显著下降(P<0.001)。总体来看,氯化钙组和20%NDF组胴体瘦肉率更高,而玉米组第42天时背膘显著增加(P<0.05)。与对照组相比,氯化钙组里脊肉pH显著降低,星形探针指标(star probe)显著增加(P<0.05)。所有处理组滴水失重、蒸煮失重、坚硬度、大理石评分没有显著差异(P≥0.117)。
      总之,试验结果说明一些日粮手段可以降低育肥猪生长速度,而不对猪的行为产生负面影响。但是,其会影响胴体组成和质量,说明在使用相关日粮措施减缓生长速度时应当考虑其对猪肉质量的影响。


Nutritional approaches to slow late finishing pig growth: implications on carcass composition and pork quality

Although pork producers typically aim to optimize growth rates, occasionally it is necessary to slow growth, such as when harvest facility capacity is limited. In finishing pigs, numerous dietary strategies can be used to slow growth so pigs are at optimal slaughter body weights when harvest facility capacity and/or access is restored. However, the impact of these diets on pork carcass quality is largely unknown. Thus, this study aimed to evaluate the efficacy of dietary strategies to slow growth in late finishing pigs and evaluate their effects on carcass composition and pork quality. Mixed-sex pigs (n = 897; 125 ± 2 kg BW) were randomly allotted across 48 pens and assigned to 1 of 6 dietary treatments (n = 8 pens/treatment): (1) Control diet representative of a typical finisher diet (CON); (2) diet containing 3% calcium chloride (CaCl2); (3) diet containing 97% corn and no soybean meal (Corn); (4) diet deficient in isoleucine (LowIle); (5) diet containing 15% neutral detergent fiber (NDF) from soybean hulls (15% NDF); and (6) diet containing 20% NDF from soybean hulls (20% NDF). Over 42 d, pen body weights and feed disappearance were collected. Pigs were harvested in 3 groups (14, 28, and 42 d on feed) and carcass data collected. From the harvest group, 1 loin was collected from 120 randomly selected carcasses (20 loins/treatment) to evaluate pork quality traits. Overall, ADG was reduced in CaCl2, Corn, and 20% NDF pigs compared with CON pigs (P < 0.001). However, ADFI was only reduced in CaCl2 and 20% NDF pigs compared with CON (P < 0.001). Feed efficiency was reduced in CaCl2 and Corn pigs compared with CON (P < 0.001). Hot carcass weights were reduced in CaCl2 pigs at all harvest dates (P < 0.001) and were reduced in Corn and 20% NDF pigs at days 28 and 42 compared with CON pigs (P < 0.001). In general, CaCl2 and 20% NDF diets resulted in leaner carcasses, whereas the Corn diet increased backfat by 42 d on test (P < 0.05). Loin pH was reduced and star probe increased in CaCl2 pigs compared with CON pigs (P < 0.05); no treatments differed from CON pigs regarding drip loss, cook loss, color, firmness, or marbling (P ≥ 0.117). Overall, these data indicate that several dietary strategies can slow finishing pig growth without evidence of behavioral vices. However, changes to carcass composition and quality were also observed, indicating quality should be taken into consideration when choosing diets to slow growth.

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