维康对肥育猪的饲喂试验

本研究旨在观察比较不同饲料添加剂对肥育猪生产性能的影响。选用体重20 kg左右的杜长大三元杂交（杜洛克×长白×大约克）瘦肉型商品猪100头,随机分为5组,每组设2个重复,每个重复10头。每组使用相同基础日粮,分别使用四种不同饲料药物添加剂进行了饲喂试验,即在基础饲粮中添加A组喹烯酮25%预混料300 mg/kg、B组维康200 mg/kg、C组维康300 mg/kg、D组北里霉素10%预混料300mg/kg的添加剂,空白对照组不添加任何添加剂。饲养时间为83 d。本试验饲养效果观察结果表明：全期日增重试验A、D组和空白对照组差异不显著（p〉0.05）,B、C组和空白对照组差异显著（p〈0.05）,B组维康按照200 mg/kg添加日增重最高,饲料报酬最高,经济效益最好。     

Betaine suppresses carnitine palmitoyltransferase I in skeletal muscle but not in liver of finishing pigs

An experiment was conducted to investigate the effect of dietary betaine supplementation on the enzyme activity and mRNA abundance for carnitine palmitoyltransferase I (CPT I) in liver and skeletal muscle of finishing pigs. Forty-eight crossbred barrows and gilts [Duroc × (Seghers × Seghers)] weighing about 55 kg were divided into two dietary treatments, each with three replicates of eight pigs (four barrows and four gilts) per replicate. Pigs were fed a corn–soybean meal basal diet supplemented with betaine at 0 or 1250 mg/kg feed for 42 days. At trial termination, two pigs (one barrow and one gilt) weighing about 90 kg were selected from each replicate (six pigs per dietary treatment) and slaughtered for analyses. The results showed that intramuscular fat content in the longissimus muscle of pigs fed betaine was 23.6% higher than that of controls (P < 0.05), whereas hepatic fat content was not affected with dietary betaine treatment. Muscle-type CPT I (M-CPT I) activity, but not liver-type CPT I (L-CPT I) activity was decreased by betaine supplementation. Furthermore, betaine supplementation reduced M-CPT I mRNA abundance by 14.6% (P < 0.05) but did not affect L-CPT I mRNA abundance. There was a positive correlation between enzyme activity and mRNA abundance for both L-CPT I and M-CPT I (r = 0.67 and r = 0.72 for L-CPT I and M-CPT I, respectively; P < 0.05). The study suggests that betaine may be involved in fat partitioning in pigs by reducing the activity and mRNA abundance of M-CPT I, with a resultant increase in intramuscular fat content.     

Effects of dibutyryl cAMP on growth performance and carcass traits in finishing pigs

This study was designed to investigate the effects of dietary supplementation with N⁶, 2′-O-dibutyryl adenosine 3′,5′-cyclic monophosphate (dbcAMP) on growth performance, carcass traits, histochemical characteristics and serum constituents in finishing pigs. Seventy-two Duroc × (Landrace × Large White) barrows (57.3 ± 0.6 kg) were randomly allotted to 3 treatments with 6 replicate pens/treatment (4 pigs/pen). The pigs were fed diets containing 0, 10 and 20 mg dbcAMP/kg, respectively, until the final slaughter weight of approximately 90 kg. There were no differences in growth performance among dietary treatments. Leaf fat proportion and first rib backfat thickness were reduced (P < 0.05), whereas tenth rib backfat thickness tended to decrease (P = 0.10), in pigs fed 10 mg dbcAMP/kg. Lean percentage was greater (P < 0.05) and longissimus muscle area tended to increase (P = 0.10) in pigs fed 10 mg dbcAMP/kg when compared to the control group, but hot carcass weight was not affected by dbcAMP. Growth rate of fat-free lean tissues tended to increase (P = 0.09) in dbcAMP-supplemented pigs. Dietary dbcAMP decreased (P < 0.05) adipocytes diameter in subcutaneous fat, whereas longissimus muscle fiber diameter tended to increase (P = 0.06) with dbcAMP supplementation; however, no difference in longissimus muscle cell density was detected among treatments. Serum concentrations of total protein and 3′,5′-cyclic adenosine monophosphate increased (P < 0.05) in response to dbcAMP, but concentrations of triglycerides, total cholesterol, glucose and urea in serum did not differ among dietary treatments. These results indicate that dbcAMP had a positive effect on carcass traits. Addition of 10 mg dbcAMP/kg to the diet was beneficial for growth performance and lean percentage, as well as improving protein and fat metabolism.     

Changes in hormones, growth factor and lipid metabolism in finishing pigs fed betaine

An experiment was conducted to investigate the effect of dietary betaine supplementation on carcass characteristics, hormones, growth factor and lipid metabolism in finishing pigs. Forty-eight crossbred barrows and gilts (Seghers × Seghers × Duroc) weighing about 55 kg were divided into two groups, each with three replicates of eight pigs (four barrows and four gilts) per replicate, and fed corn–soybean meal basal diets supplemented with 0 and 0.125% betaine for 42 days. At trial termination, two pigs (one barrow and one gilt) weighing about 90 kg were selected from each replicate and slaughtered for analyses. The results showed that betaine increased carcass lean percentage and longissimus muscle area by 5.19% (P < 0.01) and 17.85% (P < 0.01), respectively, and decreased carcass fat percentage and average backfat thickness by 13.07% (P < 0.01) and 10.30% (P < 0.05), respectively. Serum growth hormone, insulin-like growth factor I, free triiodothyronine, free thyroxine and insulin levels in pigs fed betaine were elevated by 45.61% (P < 0.01), 55.50% (P < 0.01), 57.95% (P < 0.01), 51.80% (P < 0.01) and 42.34% (P < 0.05), respectively. Fatty acid synthase activity in the 10th rib subcutaneous adipose tissue was decreased by 24.35% (P < 0.05) with betaine supplementation, whereas hormone-sensitive lipase activity was significantly increased (P < 0.05). Meanwhile, serum free fatty acids concentration in betaine-fed pigs was 25.75% higher compared to controls (P < 0.01). The study suggested that betaine could induce changes in hormones and growth factor in finishing pigs, and therefore could inhibit fat synthesis through reducing lipogenic enzymes activities and promote fat degradation by increasing hormone-sensitive lipase activity, with a resultant decrease in adipose tissue mass and improvement in carcass characteristics.     

Effects of supplemental humic substances on growth performance, blood characteristics and meat quality in finishing pigs

A total of forty-eight finishing pigs were used to determine the effects of humic substances (HS) on growth performance, blood characteristics, and meat quality. The finishing pigs were assigned randomly by weight to three treatments. The dietary treatments included: 1) Control (CON; basal diet), 2) HS1 (basal diet + 5% humic substances) and 3) HS2 (basal diet + 10% humic substances). Results of the whole experimental period showed that addition of 10% HS to the diet, significantly increased average daily gain (ADG) and gain/feed (G:F) (P < 0.05). At the end of the experiment, the relative lymphocyte counts (% of total white blood cells) of pigs fed HS2 diet were higher (P < 0.05) than that of pigs fed CON diet. The Minolta color parameter a of pigs fed HS2 was similar to that of pigs fed HS1, however, it was higher (P < 0.05) than that of pigs fed CON diet. The inclusion of either 5% or 10% HS significantly decreased backfat thickness (P < 0.05). The marbling score was increased significantly (P < 0.05) when diets were supplemented with HS at a level of 10%. The results of this study suggest that HS might be utilized as a feed additive in the diet. It could improve growth performance, relative lymphocyte counts and meat quality.     

Effects of single or carbohydrases cocktail in low-nutrient-density diets on growth performance, nutrient digestibility, blood characteristics, and carcass traits in growing–finishing pigs

This study was conducted to evaluate the effects of single or carbohydrases cocktail in low-nutrient-density diets on growth performance, nutrient digestibility, blood characteristics, and carcass traits of growing–finishing pigs. A total of 96 pigs with an average initial BW of 47.50 ± 1.25 kg were used in this 8-week growth trial. Pigs were randomly allocated to 1 of the 4 treatments according to its BW and sex (4 pigs/pen, 6 replicate pens/treatment). The diets included: 1) control (CON) corn–soybean meal diet (DE, 3400 kcal/kg; CP, 17%), 2) low-nutrient-density (LC) diet with 6% DDGS and 5% tapioca (DE, 3280 kcal/kg; CP, 15%), 3) LC + 0.05% β-mannanase (LCS), and 4) LC + 0.05% enzyme mixture (LCM). The LC treatment had a lower ADG, and G/F compared to the other treatments in 0–4 weeks and the overall period of the feeding trial (P < 0.05). The ADFI were decreased in LC, LCS, and LCM groups related to CON (P < 0.05). The LCS treatment had higher DM digestibility than pigs in both the LC and LCM groups (P < 0.05) on 4 weeks while LCM improved N and energy digestibility compared to LC treatment. Blood urea nitrogen and creatinine values were not affected by the experimental treatments. After the feeding period, pigs (2 per pen) which reached marketing BW were collected meat samples from slaughter house. Backfat thickness was decreased in LC, LCS and LCM groups (P < 0.05). No numerical differences were observed in meat color, pH value and water holding capacity among four treatments. In conclusion, the results of this study indicate that single or carbohydrases cocktail in low-density diets can partially improve ADG, G/F, nutrient digestibility, and meat quality in finishing pigs, which can counteract the negative effects caused by the decreased nutrient concentration.     

Holmium:YAG Laser Lithotripsy for Urolithiasis in Horses

Background: Laser lithotripsy has been used as an alternative to surgical removal of uroliths.
Objective: To describe the procedure and efficacy of laser lithotripsy for removal of lower urinary tract uroliths in horses. Additionally, the ultrastructure and the differences in mineralogy and microstructure from 1 successful and 1 unsuccessful laser lithotripsy case are described.
Animals: Six client-owned horses with 7 episodes of naturally occurring urocystoliths, urethroliths, or both.
Methods: Retrospective study of all horses treated between 2006 and 2008 by laser lithotripsy. All horses were sedated followed by laser lithotripsy. Quantitative urolith analysis was performed in all cases. Ultrastructure and microstructure analyses were performed on uroliths from 2 horses.
Results: Procedural success was achieved in 5 of 7 laser lithotripsy procedures. No complications occurred as a result of laser lithotripsy. One horse developed uroabdomen likely as a result of manual lithotrite disruption of the bladder after failure of laser lithotripsy. There were differences in microstructure between 1 urolith that was successfully fragmented by laser lithotripsy and 1 urolith that was resistant to laser fragmentation.
Conclusions and Clinical Importance: Laser lithotripsy is an effective procedure for removal of some urocystoliths, urethroliths, or both in horses.     

高活菌发酵饲料对生长肥育猪生产性能的影响

选用240头日龄相近、体况一致的杜×长×大三元杂交肥育猪,随机平均分为3个处理,对照组、试验1组和试验2组。对照组饲喂基础日粮加抗生素,试验1组和试验2组分别在基础日粮中添加4%和8%的高活菌发酵饲料。试验结果表明:在28d的饲养试验中,试验2组饲养效果最好,平均日增重比对照组提高12.34%,采食量增加7.90%,料肉比减少4.0%,腹泻率降低2.89%。应用高活菌发酵饲料饲喂生长肥育猪能起到促进其生长、减少腹泻以及改善仔猪肠道健康的功效。     

复合多糖对育肥猪生长性能和胴体品质的影响

试验旨在研究以牛膝、杜仲和玄参三种药用多糖进行配伍对生长育肥猪生长性能、屠宰性能和肉品质的影响,探讨复合多糖改善育肥猪生长性能及肉品质的机理。试验选用160头体重接近的生长育肥猪,采用单因素完全随机试验设计,分为5个处理:1)基础日粮组,2)抗生素组,3)0.05%复合多糖组,4)0.10%复合多糖组,5)0.15%复合多糖组。每组4个重复,每个重复8头猪,试验期共90 d。结果显示:1)与基础日粮组相比,0.10%复合多糖组和0.15%复合多糖组能显著提高猪日增重和降低料重比(P<0.05)。2)与基础日粮组相比,0.10%复合多糖组和抗生素组能显著提高猪屠宰率(P<0.05),复合多糖各组(0.05%,0.10%和0.15%)和抗生素组能显著降低猪的背膘厚并提高眼肌面积和瘦肉率(P<0.05)。3)与基础日粮组相比,复合多糖各组(0.05%,0.10%和0.15%)能显著提高猪背最长肌大理石纹评分并显著降低猪背最长肌的滴水损失(P<0.05)。与基础日粮组相比,抗生素组显著提高猪背最长肌的失水率和滴水损失(P<0.05)。结果表明复合多糖能够显著提高肌肉肉色评分、大理石纹评分、熟肉率,提高瘦肉率和肉品质。     

饲料锌在育肥猪粪尿中的排泄规律研究

为研究饲料锌在育肥猪粪尿中的排泄规律,建立饲料锌摄入量与锌排泄量的预测模型,试验选用健康、体重相近的约克夏去势育肥公猪20头,随机分成5组,每组4个重复,每个重复1头猪,单独饲养于代谢笼中。对照A组饲喂基础日粮,锌添加量为0,试验B、C、D、E组分别饲喂在基础日粮中添加20、40、60、80 mg/kg锌的试验日粮(硫酸锌形式)。预试期7 d,正试期4 d。结果表明:(1)与对照组相比,除试验B组外,其他试验各组风干粪锌含量和粪锌日排泄总量随日粮锌添加水平或日粮总锌水平增加显著升高(P<0.05);经回归分析,日粮锌添加水平或日粮总锌水平与风干粪锌含量和粪锌日排泄总量存在极显著的线性回归关系(P<0.01),可用所建立的回归方程进行预测和控制。(2)各组尿锌含量和尿锌日排泄总量均无显著差异(P>0.05);经回归分析,日粮锌添加水平或日粮总锌水平与尿锌含量和尿锌日排泄总量无显著回归关系(P>0.05)。综上,日粮中多余的锌主要通过消化道从粪中排泄,可根据日粮中锌水平预测粪锌排泄量,从源头上控制锌对环境的污染。     

Prevotella-rich enterotype may benefit gut health in finishing pigs fed diet with a high amylose-to-amylopectin ratio

To investigate the influence of baseline enterotypes and dietary starch type on the concentration of short-chain fatty acids (SCFA), numbers of butyrate producing bacteria and the expression of genes related to intestinal barrier and inflammatory response in the colon of finishing pigs, a 60-d in vivo trial was conducted. A 2-wk pre-trial with 102 crossbred (Duroc × [Landrace × Yorkshire]) finishing barrows (90 d old) was conducted to screen enterotypes. Then, a total of 32 pigs (87.40 ± 2.76 kg) with high (HPBR, ≥ 14) and low (LPBR, ≤ 2) Prevotella-to-Bacteroides ratios (PBR) in equal measure were selected and randomly divided into 4 groups with 8 replicates per group and 1 pig per replicate. The trial was designed following a 2 (PBR) × 2 (amylose-to-amylopectin ratio, AMR) factorial arrangement. Pigs with different PBR were fed diets based on corn-soybean meal with high AMR (HAMR, 1.24) or low AMR (LAMR, 0.23), respectively. Results showed that neither PBR nor AMR influenced the growth performance of pigs. HPBR pigs fed HAMR diet had a higher number of colonic Clostridium cluster XIVa and higher gene expression of butyrate kinase compared to the LPBR pigs (P < 0.05). The HPBR pigs fed HAMR diets also had increased colonic concentrations of total SCFA and propionate compared to the LPBR pigs (P < 0.05). Comparing with other pigs, HPBR pigs fed HAMR diets showed a lower (P < 0.05) expression of histone deacetylases (HDAC) gene and higher (P < 0.05) expression of G protein-coupled receptor 43 gene (GPR 43) in the colonic mucosa. The interaction (P < 0.05) of HPBR and HAMR was also found to decrease the gene expression of interleukin (IL)-6, IL-12, IL-1β and tumor necrosis factor-α (TNF-α) in colonic mucosa. These findings show that HAMR diet increased the abundance and activity of butyrate-producing bacteria and the concentration and absorption of SCFA, which may be associated with the decreased gene expression of inflammatory cytokines in the colonic mucosa of pigs with Prevotella-rich enterotype. All these alterations are likely to have a positive effect on the intestinal health of finishing pigs.     

耐热素对猪饲粮养分消化率的影响

选取杜×长×大三元杂交肥育猪48头,随机分成3组,即对照组、试验1组和试验2组。对3组猪的试验处理如下:用基础饲粮直接喂对照组猪;在基础饲粮中加0.5%耐热素A后,喂试验1组的猪;将基础饲粮中食盐含量降到0.2%,再加0.5%耐热素B后,喂试验2组的猪。饲养试验期为54d。试验结果如下:试验1、2组猪的体温均在不同程度上低于对照组猪,但差异不显著(P>0.05);在高温下,耐热素能较好地维持猪健康状态;试验1组猪饲粮中的粗纤维(CF)、粗灰分(Ash)、钙、磷的消化率均显著地高于对照组(P<0.05),粗脂肪(EE)、粗蛋白(CP)、无氮浸出物(NFE)、干物质(DM)的消化率也比对照组高,但差异不显著(P>0.05)。试验表明,耐热素A在高温下对维持猪体健康和提高饲粮养分消化率有积极的作用。     

不同复合酶制剂对肥育猪生长性能的影响

试验选用72头100日龄,体重在44kg左右的三元杂交(杜×长×大)商品代瘦肉型肥育猪,完全随机分为3个组(A、B、C),每个组24头,设三个重复。A组中,饲料中加入国产复合A酶;B组中,饲料中加入国产复合B酶;C组中,饲料中加入罗酶宝TM。经过30天的饲养试验,结果表明:①B、C两组肥育猪的日增重比A组分别提高0.81%、5.50%,C组比B组日增重提高4.65%;②C组肥育猪料重比比A组提高3.53%,C组料重比比B组提高2.59%,B组料重比比A组提高0.96%;③经济效益,C组比A、B两组分别提高8.59%、5.99%;④试验全期,三个处理组的腹泻率均极低。     

半胱胺对生长肥育猪后期生长性能的影响

选用60头体重约60kg左右的三元杂交(杜×长×大)商品代瘦肉型肥育猪,随机分为试验组和对照组两组,每组又设三个重复,每个重复10头猪。试验组饲喂添加200g/吨半胱胺含量为50%的“大丰收”(由杭州某饲料有限公司提供)的日粮,对照组日粮不添加大丰收。进行为期41天的对比试验。试验结果显示:同对照组相比试验组平均日增重、饲料转化效率、瘦肉率和胴体品质均得到不同程度的提高和改善;而且在外观上也得到明显的改善;猪后臀丰满、皮红毛亮、肌肉发达。