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.     

饲粮含硫氨基酸水平对断奶仔猪生长性能、肠道形态及酶活性的影响

文章旨在研究饲粮含硫氨基酸水平对断奶仔猪生长性能、肠道形态及酶活性的影响。试验选择体重接近的28日龄断奶仔猪80头,称重后随机分为试验1、2、3、4组,各组饲粮中含硫氨基酸含量分别0.49%、0.64%、0.79%、0.94%,共进行21d。试验结果,仔猪平均日采食量(ADFI)随着饲粮中含硫氨基酸水平增加出现先增加后下降的趋势,料肉比(F/C)与之趋势相反,当含硫氨基酸含量为0.79%时(试验3组)生长性能最好。其中,试验2、3组仔猪平均日增重(ADG)较试验1组分别增加12.5%、15.9%(P<0.05),F/C较试验1组分别降低10.8%、12.4%(P<0.05)。饲粮中含硫氨基酸水平显著影响仔猪空肠形态,而对十二指肠、回肠形态无显著影响(P>0.05)。相比于试验1组,试验2、3、4组空肠绒毛高度(VH)分别增加8.6%、11.7%、9.1%(P<0.05),空肠隐窝深度(CD)分别下降22.6%、16.4%、12.7%(P<0.05),试验2、3组绒毛高度和隐窝深度比(V/C)较试验1组分别增加24.3%、17.4%(P<0.05)。除此之外,饲粮中含硫氨基酸显著影响仔猪空肠中碱性磷酸酶(ALP)活性(二次P<0.05)及麦芽糖酶活性(P<0.05)。综上所述,饲粮中含硫氨基酸水平显著影响断奶仔猪小肠发育及空肠内酶活性,改善生长。     

Effects of different sulphur amino acids and dietary electrolyte balance levels on performance,jejunal morphology,and immunocompetence of broiler chicks

As alterations of dietary electrolyte balance (DEB) can influence amino acid metabolism via changes the ions incur in their configurations, performance and immunological responses of broiler chicks might be affected. So, the current study was carried out to investigate the effects of different levels of sulphur amino acids (SAA) and DEB on performance, jejunal morphology and immunocompetence of broiler chicks. A total of 360 1‐day‐old male Ross 308 broiler chicks were randomly assigned to nine experimental treatments with four replicates of 10 birds each. Experimental treatments consisted of three levels of SAA (100, 110, and 120% of NRC recommendation, provided by methionine supplementation in diets with the same cysteine level) and three levels of DEB (150, 250, and 350 mEq/kg) that were fed during the entire of trial in a 3 × 3 factorial arrangement. Results showed that the relative weights of intestine and abdominal fat were decreased markedly (p < 0.001) with increasing levels of SAA and DEB respectively. Antibody titre against sheep red blood cell was neither individually nor in combination influenced by supplementation of SAA or DEB. Nevertheless, a decrease in DEB level led to a suppression in heterophile (p < 0.05) and an increase in lymphocyte counts (p = 0.06); consequently, heterophile to lymphocyte ratio was significantly decreased (p < 0.05) by decremental levels of DEB. Albumin to globulin ratio was increased after inclusion of at least 10% SAA (p < 0.001) and 150 mEq DEB/kg in the diet (p = 0.11). Although feeding high‐DEB level led to a remarkable decrease in villus height (p < 0.01) and goblet cell numbers (p < 0.001), supplementing the highest level of SAA improved the height of jejunal villus. During the entire trial period, average daily feed intake (ADFI) was increased by incremental SAA levels (p < 0.05). However, inclusion of 150 mEq/kg led to not only a remarkable increase (p < 0.0001) in both ADFI and average daily weight gain (ADWG) but also to improved (p < 0.001) feed conversion ratio (FCR) both during the growing and over the entire trial periods. The present findings indicated that inclusion of low DEB decreased the heterophile to lymphocyte ratio and improved both the albumin to globulin ratio and intestinal health indices. The best growth performance was obtained with 150 mEq DEB/kg in the diet for each level of SAA.     

液态或颗粒饲料添加精氨酸对21～42 d断奶仔猪生长性能和血浆氨基酸水平的影响

文章旨在研究饲喂颗粒料或液态料以及日粮添加精氨酸对断奶仔猪生长性能及血浆必需氨基酸和非必需氨基酸含量的影响。试验选择21 d断奶的健康仔猪672头,随机分为4组,每组6个重复,每个重复28头。试验日粮采用2×2多因素方差设计,2种饲料形态(液态料或颗粒料),2个精氨酸水平(0或6 g/kg精氨酸),试验共进行21 d。断奶后前10 d饲喂液态料较颗粒料显著改善了仔猪的平均日采食量、平均日增重和料比(P<0.05);在断奶后第11~13天液态料向颗粒料过渡阶段,液态料组较颗粒料组对日增重和料比具有负面影响(P<0.05);饲料形态和添加精氨酸以及饲料形态和仔猪日龄对断奶仔猪的平均日采食量的影响具有显著交互效应(P<0.05)。断奶后前10 d,饲喂液态料的仔猪较颗粒显著提高了干物质摄入量(P<0.05);断奶后前10 d饲喂添加精氨酸的液态料仔猪,由液态料向固体料过渡,显著提高了采食量和日增重(P<0.05)。液态或颗粒饲料添加精氨酸显著降低了断奶仔猪血浆尿素氮含量(P<0.05);饲喂液态料的断奶仔猪在28和37 d较颗粒料组显著降低了血浆尿素氮含量(P<0.05)。除了色氨酸、组氨酸、谷氨酸和甘氨酸外,液态料较颗粒料均显著提高了断奶仔猪血浆氨基酸水平(P<0.05);颗粒料或液态料添加精氨酸显著提高了断奶仔猪血浆亮氨酸、异亮氨酸、精氨酸和甘氨酸水平(P<0.05)。综上所述,断奶后仔猪饲喂液态料可以提高生长性能,但无论颗粒料还是液态料添加精氨酸均可以显著提高血浆精氨酸水平,降低尿素氮含量。     

陈化大米替代玉米对断奶猪生长性能、血液生化及游离氨基酸水平的影响

本研究旨在研究用陈化大米完全替代玉米对仔猪断奶后1～28?d生长性能、血液生化及游离氨基酸水平的影响.试验将21?d断奶、平均初始体重为(6.32±0.09)kg的480头仔猪随机分为2组,每组8个重复,每个重复30头.两组断奶仔猪在28?d的试验期中分别饲喂玉米和陈化大米为主的日粮.结果:与玉米组相比,陈化大米组仔猪...     

Effects of dietary supplementation with betaine on muscle growth,muscle amino acid contents and meat quality in Cherry Valley ducks

The effects of dietary betaine supplementation on growth performance, carcass characteristics, muscle amino acid contents, meat quality, antioxidant capacity, myogenic gene expression and mechanistic target of rapamycin (mTOR) signalling pathway in Cherry Valley ducks were evaluated. A total of 720 1‐day‐old Cherry Valley ducks were randomly distributed into four groups with six replicates of 30 birds for a 42‐day feeding trial. Ducks were fed a basal diet supplemented with 0 (control), 250, 500 or 1,000 mg/kg betaine, respectively. Growth performance was not affected by betaine. Incremental levels of betaine linearly (p < 0.05) increased the breast muscle yield and linearly (p < 0.05) decreased the subcutaneous fat thickness and the abdominal fat yield. The contents of methionine, serine, glycine, glutamate and total non‐essential amino acid in breast muscle were linearly (p < 0.05) increased by betaine supplementation. With increasing betaine levels, the drip loss and the content of malondialdehyde (MDA) were linearly (p < 0.05) decreased, and the redness of meat (linear p < 0.05), the activities of catalase (CAT) (linear p < 0.05) and total superoxide dismutase (T‐SOD) (linear p < 0.05, quadratic p < 0.05) were increased. Moreover, the myogenic differentiation factor 1 (MyoD1) mRNA expression and the mTOR mRNA expression and protein phosporylation were linearly (p < 0.05) up‐regulated, and the myostatin (MSTN) mRNA expression was linearly (p < 0.05) down‐regulated by betaine supplementation. Overall, this study indicated that betaine supplementation did not affect the growth performance of Cherry Valley ducks, but could linearly increase some amino acid contents in breast muscle, especially glycine, and increase muscle antioxidant activity to improve meat quality. Moreover, betaine supplementation could improve the breast muscle yield by increasing MyoD1 mRNA expression, decreasing MSTN mRNA expression and regulating mTOR signalling pathway.     

Effects of dietary water‐soaked barley on amino acid digestibility,growth performance,pork quality and Longissimus dorsi muscle fatty acid profiles in pigs

Two experiments were conducted to assess the feeding value of water‐soaked barley (WB) as a replacement for dehulled barley (DB) in pigs. In experiment (Exp.) 1, eight barrows (body weight = 30.56 ± 0.78 kg) were fitted with a T‐cannula and allotted to a duplicated 4 × 4 Latin square design: WB10, 100g/kg WB; WB20, 200 g/kg WB; DB10, 100 g/kg DB; and DB20, 200 g/kg DB. In Exp. 2, 80 barrows (body weight = 70.56 ± 1.29 kg) were used in a 56‐day experiment: (i) WB15, 150 g/kg WB; (ii) WBD10, 100 g/kg WB and 50 g/kg DB; (iii) WBD5, 50 g/kg WB and 100 g/kg DB; and (iv) DB15, 150 g/kg DB. In Exp. 1, the apparent ileal digestibilities of total essential amino acids were higher (P < 0.05) in WB10 treatment than DB20. For Exp.2, the WB15 and WBD10 had higher pH and lower cooking loss (P < 0.05) than other two treatments. The WB15 treatment decreased (P < 0.05) the contents of palmitic acid (C16:0) in Longissimus dorsi muscle than WBD5 and DB15 treatments. In conclusion, it is suggested that water‐soaked barley improved some amino acid digestibility and the cooking loss and moderate fatty acid profiles in Longissimus dorsi muscle.     

Influence of dietary rapeseed meal levels on growth performance,organ health and standardized ileal amino acid digestibility in meat ducks from 15 to 35 days of age

This study was conducted to investigate the effects of dietary rapeseed meal (RSM) inclusion levels on growth performance, organ health and standardized ileal amino acid digestibility (SIAAD) in meat ducks from 15 to 35 days of age. Six hundred and eighty 15‐days‐old ducks were randomly allotted to five treatments based on body weight. Five isonitrogenous and isoenergetic diets were formulated on a digestible amino acid basis by replacing 0% (the control), 25%, 50%, 75% and 100% (based on fresh) of protein from soya bean meal (SBM) with protein from RSM. The corresponding levels of RSM in experimental diets were 0%, 6.66%, 13.32%, 19.98% and 26.64% respectively. With increasing dietary RSM levels, body weight (BW) and average daily gain (ADG) linearly decreased (p < 0.001), whereas feed‐to‐gain ratio (F: G) linearly increased (p = 0.0078). Ducks fed the diets with 13.32% or more RSM had significantly lower (p < 0.05) BW, ADG and ADFI, or higher F: G than ducks fed the control diet. The maximum limit of dietary RSM supplementation was estimated to range from 4.27% to maximize ADG for 15 to 35 days to 11.69% to maintain feed intake for 15 to 35 days on the basis of a broken‐line model. At day35, the 4th primary wing feather length and SIAAD (except for Met, Thr and Val) linearly decreased (p < 0.001), and the thyroid glands weight (% of BW) linearly increased (p < 0.05) with increasing dietary RSM levels. Ducks fed the RSM inclusion diets had significantly lower (p < 0.0001) serum aspartate aminotransferase (AST) and alanine transaminase (ALT) activities than ducks fed the control diet. These results suggested that the maximum limit of dietary RSM containing 7.57 μmol/g glucosinolates was estimated to be 4.27% to avoid growth reduction.     

Corn protein has greater concentrations of digestible amino acids and energy than low-oil corn distillers dried grains with solubles when fed to pigs but does not affect the growth performance of weanling pigs

Three experiments were conducted to test the hypothesis that standardized ileal digestibility (SID) of amino acids (AA) and digestible energy (DE) and metabolizable energy (ME) in a new source of corn protein are greater than in corn distillers dried grains with solubles (DDGS) and that corn protein may be included in diets for weanling pigs. In experiment 1, the SID of AA was determined in two sources of DDGS (DDGS-1 and DDGS-2) and in corn protein. Results indicated that SID of most AA was greater (P < 0.05) in DDGS-2 and corn protein than in DDGS-1, but corn protein contained more digestible AA than both sources of DDGS. In experiment 2, the DE and ME in corn, the two sources of DDGS, and corn protein were determined. Results demonstrated that DE (dry matter basis) in corn protein was greater (P < 0.05) than in corn, but ME (dry matter basis) was not different between corn and corn protein. However, DE and ME in corn (dry matter basis) were greater (P < 0.05) than in DDGS-1 and DDGS-2. In experiment 3, 160 weanling pigs were allotted to four treatments in phases 1 and 2 and a common diet in phase 3. Corn protein was included at 5% to 10% in phases 1 and 2 at the expense of plasma protein and enzyme-treated soybean meal. Results indicated that although differences in average daily gain and gain to feed ratio were observed in phase 1, no differences among treatments were observed for the overall experimental period. In conclusion, the concentration of digestible AA is greater in corn protein than in DDGS; DE and ME in corn protein are also greater than in DDGS; and up to 10% corn protein may be included in phase 1 and phase 2 diets for weanling pigs.