Effects of 2‐hydroxy‐4‐(methylthio) butanoic acid isopropyl ester on growth and blood components in growing Holstein steers

Twenty‐four Chinese Holstein growing steers were randomly divided into three groups and fed a diet containing 0 (the control group), 15 (treatment I group, or TG1) or 25 (treatment II group, or TG2) g/day 2‐hydroxy‐4‐(methylthio) butanoic acid isopropyl ester (HMBi). Compared with the control group, the final body weights, total gains and average daily gains in the treatment groups increased (P < 0.01). The concentration of total protein (TP) for TG1 increased (P < 0.01). The levels of albumin in TG1 were higher than those in TG2 and the control group (P < 0.05). The concentration of alanine aminotransferase (ALT) in TG2 increased (P < 0.05), but concentrations of aspartate aminotransferase (AST) in the treatment groups decreased (P < 0.05). HMBi improved the concentrations of selenium in both TG1 (P < 0.05) and TG2 (P < 0.01). The levels of glutathion peroxidase (GSH‐Px) in TG2 were higher than those of the control group (P < 0.05). Moreover, HMBi increased the concentrations of growth hormone (GH) in both TG1 (P < 0.05) and TG2 (P < 0.01). These results indicate that the addition of HMBi increases growth performance, serum concentrations of GH and AST; 15 g/day HMBi increases concentrations of total protein and albumin, and 25 g/day HMBi increases concentrations of ALT and GSH‐Px.     

Effects of addition of Aspergillus oryzae culture and 2‐hydroxyl‐4‐(methylthio) butanoic acid on milk performance and rumen fermentation of dairy cows

To investigate effects of Aspergillus oryzae culture (AOC) and 2‐hydroxy‐4‐(methylthio) butanoic acid (HMB) on milk performance and rumen fermentation of dairy cows. Sixty‐four multiparous Chinese Holstein cows were randomly allocated into four experimental diets: (i) Control diet; (ii) AOC diet: 5 g AOC/day per head; (iii) HMB diet: 25 g HMB/day; and (iv) AH diet: 5 g AOC plus 25 g HMB/day. Added HMB tended to increase the yield of milk protein (P = 0.06) and 3.5% fat‐corrected milk (P = 0.08) and milk fat content (P = 0.09). Milk fat yield (P = 0.03) and the contents of milk protein (P = 0.05) were increased by adding HMB. The cows fed on AOC diet had a tendency for higher body weight (BW) gain (P = 0.08). Addition of AOC, HMB and AH increased content of microbial protein (MCP) and total volatile fatty acids (VFA) (P < 0.01) in rumen fluid. Populations of rumen fungi, Fibrobacter succinogenes and Ruminococcus flavefaciens relative to total bacterial 16S rDNA (P ≤ 0.03) and activity of carboxymethylcellulase (CMCase) (P < 0.01) were increased with added AOC or HMB. It is inferred that added AOC or HMB can increase the contents of MCP and total VFA potentially by stimulating rumen microbe populations and CMCase activity.     

Effects of DL-2-hydroxy-4-(methylthio) butanoic acid on broilers at different dietary inclusion rates

1. A growth experiment was conducted to determine the effectiveness of liquid analogue, DL-2-hydroxy-4-(methylthio) butanoic acid (HMTBA), compared to powder DL-methionine (DLM), in commercial maize–soybean-meal broiler diets similar to those commonly used in China, on feed conversion ratio (FCR), growth performance and European Production Index (EPI) of broilers.

2. A 4 × 2 + 1 factorial arrangement of treatments was used in which HMTBA or DLM was fed at 4 concentrations (low, medium, high and very-high inclusion rates) of supplementation at 100% equivalence on an equimolar basis. Negative control diets were commercial starter, grower and finisher feeds with no added methionine. A total of 1008 commercial-type Arbor Acres 1-d-old chicks were randomly distributed into 9 groups, with 8 replicates of 14 (7 male + 7 female) birds per treatment.

3. The body weight gain of the control group was significantly lower than that of the others in the starter period but did not show any differences during the other periods. The FCR of the control group was higher than that of the others except for those with HMTBA in the grower period. It was also observed that the FCR dropped as the supplemented concentration of methionine was increased regardless of the source. Some of the treatment groups produced a better breast yield than the control. The EPI between the two products did not show any significant difference.

4. In conclusion, both of the methionine sources were equally effective in ameliorating the effects of a dietary deficiency of total sulphur amino acids.

     

2‐Hydroxy‐4‐methylthio butanoic acid and DL‐methionine for Japanese quails in production

An experiment was performed using 1,000 laying Japanese quails to assess the availability of two alternative dietary methionine sources. Treatment 01 = Basal Feed that is deficient in digestible methionine + cystine (Met + Cys). The other treatments were constituted by Met + Cys levels of 0.8, 1.60 and 2.40 g/kg, supplemented with DL‐Methionine‐99%, HMTBA‐88% and HMTBA‐84%, being 10 treatments in total. The following characteristics were studied: feed intake (g/bird/day), egg production (egg/day × 100), egg weight (g/egg), egg mass (g/egg), feed conversion per egg dozen (kg feed/dozen eggs), feed conversion per egg mass (kg feed/kg eggs), relative yolk weight (g/100 g of egg), relative albumen weight (g/100 g of egg), relative shell weight (g/100 g of egg), shell thickness (mm) and specific gravity (g/cm³). In general result comment, supplemental methionine sources must be included in the poultry diet. The different methionine sources affect the performance of quails, and the increase in the levels within each source improves the performance variables. Significant effect was observable on performance variables and egg quality variables, being that DLM‐99% is superior to the other sources. The HMTBA‐88% source is superior to the HMTBA‐84% source for the same aforementioned variables. In conclusion, the bioefficacy values of the HMTBA‐88% and HMTBA‐84% sources compared to the DLM‐99% source on an equimolar basis were 81 and 79%, respectively, for the performance variables, and 83 and 74 while the methionine sources were equivalent for the variables related to egg quality.     

Digestibility,ruminal fermentation,blood metabolites and antioxidant status in ewes supplemented with DL‐methionine or hydroxy‐4 (methylthio) butanoic acid isopropyl ester

The effects of supplementing ewe diets with either DL‐methionine (DL‐Met) or 2‐hydroxy‐4 (methylthio) butanoic acid isopropyl ester (HMBi) were investigated on ruminal in situ degradability of grain and forage diets, in vivo digestibility, rumen fermentation, blood metabolites and antioxidant status. Six ruminally cannulated ewes were used in a replicated 3 × 3 Latin square design with 28‐day periods. The dietary treatments were as follows: (i) no supplemental Met (control; CON), (ii) DL‐Met at 1.2 g/kg DM intake and (iii) HMBi at 1.8 g/kg dry matter (DM) intake. Corn grain, barley grain and alfalfa hay were evaluated for their ruminal degradability by both in situ incubation and effective degradability measurements of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Compared to other treatments, HMBi supplementation increased (p < 0.05) the digestibility of organic matter, crude protein and NDF and also tended (p = 0.08) to increase the digestibility of DM and ADF. Moreover, HMBi supplementation increased (p < 0.01) total VFA concentrations, the molar proportions of valerate and iso‐butyrate in the rumen. Compared to the CON treatment, DL‐Met and HMBi treatments tended (p = 0.08) to increase the molar proportion of acetate but decreased (p < 0.05) ruminal ammonia‐N concentration. Ewes supplemented with HMBi and DL‐Met recorded greater (p < 0.05) serum concentrations of glutathione peroxidase, total antioxidant capacity and superoxide dismutase than the CON treatment. Serum concentrations of glucose, total protein, albumin, high‐density lipoprotein and very low‐density lipoprotein were greater (p < 0.01) and serum urea nitrogen (p < 0.05), malonyl dialdehyde and triglyceride were lower (p < 0.02) in the HMBi and DL‐Met animals than in the CON ewes. The results concluded that HMBi is a very effective form of dietary Met supplementation for ewes with a positive effect on digestion, rumen fermentation and serum antioxidant function.     

Impact of feeding 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine supplemented maize-soybean-rapeseed meal diets on growth performance and carcase quality of broilers

1. This experiment was conducted to compare the effectiveness of DL-2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and DL-methionine (DLM) on growth performance and carcase quality of broilers in a 2 x 3 x 2 factorial experimental design including two methionine (Met) sources, three equimolar levels of Met supplementation and two sexes. 2. No difference was observed between the two Met sources in growth performance and muscle deposition from 10 to 49 d. With increasing Met levels, average daily gain was increased in the starter, grower and overall phases, average daily feed intake was increased in the starter phase, and feed:gain ratio was decreased in the grower and overall phases. Met supplementation increased breast muscle content and decreased abdominal fat content. Broilers given HMTBA had breast and thigh muscle coloration that was characterised as superior to those fed DLM. 3. These results indicated that Met supplementation improved growth performance and carcase quality irrespective of the Met sources. Compared to DLM, HMTBA has the same molar bioefficacy for improving the growth performance and carcase quality; however, HMTBA-fed birds had superior meat colour to DLM-fed birds.     

蛋氨酸羟基类似物(HMTBA)对肉鸡正常和攻毒状态下生产性能的影响

在体外试验以及预试验的基础上,通过对日粮中添加HMTBA、杆菌肽锌和益生菌,考察其对正常以及沙门氏菌CVCC518攻毒情况下肉鸡生产性能的影响。将300只雄性健康AA肉鸡随机分为5个日粮组,每组6个重复,每个重复10只鸡。试验期为42 d,分为前期(1～21 d)、后期(22～42 d),饲喂玉米-豆粕型基础日粮。结果表明:正常组中,各处理日粮都不同程度地改善了肉鸡的生产性能;HMTBA、益生菌和抗生素能够显著提高22～42 d肉鸡的日增重(P<0.05),抗生素组显著降低了22～42 d、1～42 d肉鸡的料重比(P<0.05);攻毒组中,各处理日粮都不同程度地改善了肉鸡各阶段的生产性能,但差异不显著(P>0.05)。     

复合酸化剂的日粮酸化作用及对营养物质表观消化率的影响

选择1日龄AA肉仔鸡450只,随机分成6组(对照组和5个试验组),研究不同添加水平复合酸化剂的日粮酸化作用及对营养物质消化率的影响,5个试验组日粮中的酸化剂添加量分0.1%、0.15%、0.2%、0.25%和0.3%。结果表明:添加复合酸化剂复合酸化剂显著降低了日粮的pH及系酸力,显著提高了各阶段日粮蛋白、能量、干物质、钙和磷的表观消化率,且以添加0.15%的作用效果最好。     

Absorption of 2-hydroxy-4-(methylthio)butanoic acid by isolated sheep ruminal and omasal epithelia

Alimet (Novus Inter., Inc., St. Louis, MO) feed supplement (an 88% aqueous solution of 2-hydroxy-4-(methylthio) butanoic acid; HMB) is a source of L-Met commonly used in nonruminants and ruminants. The absorption of HMB across ovine omasal and ruminal epithelia was evaluated in this study. Ruminal and omasal epithelia were collected from eight lambs (BW = 67.6 kg +/- 9.1) and mounted in parabiotic chambers that were repeatedly sampled throughout a 60-min incubation. The appearance of HMB (using DL-[5-14C]-HMB as a radiolabeled marker) in serosal buffers increased quadratically (P < .004) with time in both tissues. More (P < .001) HMB appeared in the serosal buffers with omasal than with ruminal epithelia. Both tissues responded similarly, and, after 60 min of incubation, the accumulation of HMB within the tissues increased linearly (P < .001) as substrate concentration (.375, .75, 1.5, 3.0, 6.0, and 12.0 mM) increased in mucosal buffers. As the concentration of HMB in the mucosal buffers increased, there was a quadratic (P < .001) increase in the appearance of HMB in the serosal buffer of the omasal epithelium, indicating some saturation of the system. The increase in serosal appearance of HMB was linear (P < .001) with ruminal tissue. The results indicate that there are probably multiple mechanisms involved in the absorption of HMB. Because saturation was observed in the omasum, it is likely that mediated transport accounts for at least a portion of the absorption of HMB in the omasum. Other mechanisms (e.g., diffusion and(or) paracellular absorption) are responsible for the balance of the absorption. Omasal epithelium appears to have a greater capacity for HMB absorption than ruminal epithelium. The enzymes involved in the conversion of HMB to 2-keto-4-(methylthio)butanoic acid were found in ruminal and omasal epithelia, liver and kidney. These results indicate that HMB can be absorbed across ruminal and omasal epithelium and that HMB can be used as a source of L-methionine.     

黑麦作为能量原料对肉鸡细菌移位、肠道黏度及微生物组成的影响

本研究开展了两批试验,旨在评估黑麦作为能量饲料原料对肉鸡细菌移位、小肠黏度和完整性、肠道微生物含量及胫骨钙化的影响。每个试验分别选择40只1日龄肉鸡,随机分为两组,对照组饲喂玉米型日粮,试验组饲喂黑麦型日粮,在10d时,两批试验各组分别选择10只鸡口服2.0mg/mL葡萄糖荧光素,2.5h后检查血清葡萄糖荧光素含量,收集肝脏用于分析细菌移位,十二指肠、回肠和盲肠用于分析微生物含量及肠道黏度,胫骨用于测定强度和分析骨成分。试验结果:两批试验中,黑麦日粮组肉鸡体重均显著低于玉米日粮组(P<0.05),但黑麦日粮组较玉米日粮组显著提高了小肠黏度(P<0.05),同时伴随高水平的血清葡萄糖荧光素和肝脏细菌移位(P<0.05)。试验1和试验2黑麦日粮组较玉米日粮组均显著提高了十二指肠、回肠和盲肠乳酸杆菌含量(P<0.05)。同时,黑麦组日粮肉鸡十二指肠和回肠大肠杆菌含量显著升高(P<0.05),而总厌氧菌含量仅在十二指肠表现为显著升高(P<0.05)。与黑麦日粮组相比,两批试验中,玉米日粮组肉鸡胫骨强度以及灰分、钙和磷含量较均显著提高(P<0.05)。结论:黑麦作为肉鸡日粮能量原料来源增加了鸡肠道黏度和体重,降低了血清葡萄糖荧光素,改变了鸡的微生物群组成和胫骨矿化。     

酸化剂与益生菌混合制剂对广西三黄鸡生长性能、屠宰性能及肉品质的影响

试验旨在研究日粮酸化剂与益生菌混合制剂对广西三黄鸡生长性能、屠宰性能及肉品质的影响。试验选取2 400只84日龄的广西三黄鸡,并将其随机分为A、B、C、D四组,每组设置3个重复,每个重复200只鸡。A组(对照组):基础日粮;B组:基础日粮+1 g/kg混合制剂;C组:基础日粮+2 g/kg混合制剂;D组:基础日粮+0.1 g/kg恩拉霉素。结果表明:试验组平均日采食量均高于对照组,其中C、D组显著高于A组(P<0.05);试验组的屠宰率均高于对照组,其中C组显著高于A组(P<0.05);试验组胸肌和腿肌的滴水损失均低于对照组,其中C组显著低于A组(P<0.05);D组腿肌的剪切力显著高于其他3组(P<0.05);试验组胸肌和腿肌的肌内脂肪均高于对照组,其中B组胸肌的肌内脂肪显著高于A组(P<0.05)。综上所述,在日粮中添加2 g/kg酸化剂与益生菌混合制剂,有助于提高三黄鸡的生长性能和屠宰性能,并能通过降低滴水损失来改善肉质。     

Effects of alpha‐lipoic acid supplementation on growth performance,antioxidant capacity and biochemical parameters for ammonia‐exposed broilers

In order to estimate the effect of alpha‐lipoic acid (LA) supplementation on relieving ammonia stress of broilers, 180 22‐day‐old male broilers were assigned to three groups, six replicates in each group and 10 birds per replicate. The three groups were: (1) a control group without ammonia stress; (2) exposure to 70 ppm atmospheric ammonia (AM); (3) exposure to 70 ppm atmospheric ammonia and administration of 300 mg/kg LA (AM + LA). The experimental period was 3 weeks. Results showed that average daily weight gain was increased and feed conversion ratio was decreased in the AM + LA group, compared with the AM group (P < 0.05). Total superoxide dismutase and glutathione peroxidase activities in serum, and glutathione content in liver were higher in the AM + LA group than that in the AM group (P < 0.05); however, serum malondialdehyde content was decreased by LA addition (P < 0.05). Additionally, serum glutamic‐pyruvic transaminase, creatine kinase and lactate dehydrogenase activities were reduced and albumin level was increased by LA addition (P < 0.05). In conclusion, LA addition could relieve ammonia stress to restore broiler production performance to normal levels.     

Effect of L‐theanine on meat quality,muscle amino acid profiles,and antioxidant status of broilers

This study investigated the effect of L ‐theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1‐day‐old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500 mg/kg L ‐theanine for 42 consecutive days. The results showed that L ‐theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p < .05). Meanwhile, drip loss, cooking loss, shear force, L*_24h, and muscle lactate content decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), while pH_24h and muscle glycogen content were quadratically improved by L ‐theanine (p < .05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L ‐theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p < .05). In conclusion, L ‐theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600 mg/kg based on the present study.     

Increased fatty acid β‐oxidation as a possible mechanism for fat‐reducing effect of betaine in broilers

Two hundred and forty 1‐day‐old male Arbor Acres broiler chickens were randomly assigned to five dietary treatments with six replicates of eight chickens per replicate cage for a 42‐day feeding trial. Broiler chickens were fed a basal diet supplemented with 0 (control), 250, 500, 750 or 1000 mg/kg betaine, respectively. Growth performance was not affected by betaine. Incremental levels of betaine decreased the absolute and relative weight of abdominal fat (linear P < 0.05, quadratic P < 0.01), low‐density lipoprotein cholesterol (LDL‐C), triglyceride (TG) and total cholesterol (TC) (linear P < 0.05), and increased concentration of nonesterified fatty acid (NEFA) (linear P = 0.038, quadratic P = 0.003) in serum of broilers. Moreover, incremental levels of betaine increased linearly (P < 0.05) the proliferator‐activated receptor alpha (PPARα), the carnitine palmitoyl transferase‐I (CPT‐I) and 3‐hydroxyacyl‐coenzyme A dehydrogenase (HADH) messenger RNA (mRNA) expression, but decreased linearly (P < 0.05) the fatty acid synthase (FAS) and 3‐hydroxyl‐3‐methylglutaryl‐CoA (HMGR) mRNA expression in liver of broilers. In conclusion, this study indicated that betaine supplementation did not affect growth performance of broilers, but was effective in reducing abdominal fat deposition in a dose‐dependent manner, which was probably caused by combinations of a decrease in fatty acid synthesis and an increase in β‐oxidation.     

Effect of resveratrol on growth performance,rectal temperature and serum parameters of yellow‐feather broilers under heat stress

This study investigated the effect of dietary resveratrol supplementation on growth performance, rectal temperature, and serum parameters of yellow‐feather broilers under heat stress. A total of 480 yellow‐feather broilers (28‐day‐old) were randomly allotted to five groups with six replicates. A thermoneutral group (TN) (24 ± 2°C) received a basal diet and another four heat‐stressed groups (37 ± 2°C for 8 hr/day and 24 ± 2°C for the remaining time) were fed the basal diet or basal diet with 200, 350, and 500 mg/kg resveratrol for 14 consecutive days. The results revealed that resveratrol supplementation improved average daily gain (p = 0.001), and decreased (p < 0.05) rectal temperature from d 3 when compared with heat‐stressed group without resveratrol. In addition, supplementation with resveratrol at 350 or 500 mg/kg lowered (p < 0.05) the contents of corticosterone, adrenocorticotropic hormone, cholesterol, triglycerides, uric acid, malonaldehyde, and activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, increased (p < 0.05) the levels of triiodothyronine, the ratio of triiodothyronine to thyroxine, total protein, glutathione, and activities of alkaline phosphatase, total superoxide dismutase, catalase, and glutathione peroxidase, though with few fluctuation. In conclusion, supplementation with resveratrol can improve the growth performance by positively regulating serum metabolic parameters and alleviating tissue oxidant damage of broilers under heat stress.     

In vitro effects of inulin and soya bean oligosaccharide on skatole production and the intestinal microbiota in broilers

The experiment was conducted to investigate the in vitro effects of inulin and soya bean oligosaccharide (SBO) on the metabolism of L‐tryptophan (L‐try) to skatole production, and the intestinal microbiota in broilers. Treatments were as follows: caecal microbiota control (Cc), Cc + inulin, Cc + SBO, rectal microbiota control (Rc), Rc + inulin and Rc + SBO. Microbial suspensions were anaerobically incubated at 38°C for 24 hr. The results showed that concentrations of skatole and acetic acid were significantly lower in caecal microbiota fermentation broth (MFB) than those in rectal MFB (p < .05). Addition of inulin or SBO significantly decreased the concentrations of indole and skatole and rate of L‐try degradation (p < .05). Inulin groups had lower indole than SBO groups (p < .05). PCR‐DGGE analysis revealed that addition of inulin or SBO decreased the microbiota richness (p < .05), but no significant differences in Shannon index (p > .05). Four distinct bands were detected in inulin and SBO groups, which were related to two of Bacteroides, one of Firmicutes and Bifidobacteria. Six bands were detected only in control groups, which represented uncultured Rikenellaceae, Roseburia, Escherichia/Shigella dysenteriae, Bacteroides uniformis (T), Parabacteroides distasonis and Enterobacter aerogenes. Populations of Lactobacilli, Bifidobacteria and total bacteria in inulin groups were higher than those in control groups (p < .05). For SBO groups, only population of total bacteria increased (p < .05). However, there were no significant differences in Escherichia coli population among treatments (p > .05). These results suggest that reduced concentrations of skatole and indole in the presence of inulin and SBO may be caused by decrease in L‐try degradation rate, which were caused by change in microbial ecosystem and pH value. Uncultured B. uniformis (T) and E. aerogenes may be responsible for degradation of L‐try to skatole.     

Effect of super dosing of phytase on growth performance,ileal digestibility and bone characteristics in broilers fed corn–soya‐based diets

A feeding trial was designed to assess the effect of super dosing of phytase in corn–soya‐based diets of broiler chicken. One hundred and sixty‐eight day‐old broilers were selected and randomly allocated to four dietary treatment groups, with 6 replicates having 7 chicks per treatment group. Two‐phased diets were used. The starter and finisher diet was fed from 0 to 3 weeks and 4 to 5 weeks of age respectively. The dietary treatments were consisted of normal phosphorus (NP) group without any phytase enzyme (4.5 g/kg available/non‐phytin phosphorus (P) during starter and 4.0 g/kg during finisher phase), three low‐phosphorus (LP) groups (3.2 g/kg available/non‐phytin P during starter and 2.8 g/kg during finisher phase) supplemented with phytase at 500, 2500, 5000 FTU/kg diet, respectively, to full fill their phosphorus requirements. The results showed that super doses of phytase (at 2500 FTU and 5000 FTU/kg) on low‐phosphorus diet improved feed intake, body weight gain, ileal digestibility (serine, aspartic acid, calcium, phosphorus), blood P levels and bone minerals such as calcium (Ca), P, magnesium (Mg) and zinc (Zn) content. It could be concluded that super doses of phytase in low‐phosphorus diet were beneficial than the normal standard dose (at 500 FTU/kg) of phytase in diet of broiler chicken.