饲用酶制剂在肉鸡日粮中的应用研究进展

本文从作用机理，影响作用的因素及饲料喂效果等几方面阐述了酶制剂在肉鸡饲养中的研究进展。     

酶制剂对肉鸡生产性能的影响

试验与国内外酶制剂加以比较,观察酶制剂(佳美酵素)对肉鸡生产性能的影响。结果表明,日粮中添加300g/t和500g/t佳美酵素在肉鸡生产性能方面显示出了良好的改善作用。     

Breeder age affects small intestine development of broiler chicks with immediate or delayed access to feed

1. The relationship between breeder age and chick gastrointestinal tract development to 21 days of age, as influenced by immediate or delayed access to feed, was examined in three consecutive trials.

2. Ross 708 chicks, derived from breeder flocks at 31 (young), 40 (middle) and 63 (old) weeks of age were placed randomly into either a control group with immediate access to feed and water, or a 48?h feed delayed (FD) group with free access to water.

3. FD negatively affected body weight (BW) of chicks derived from young and old flocks through the first and second weeks of age, respectively. Chicks from the older flock absorbed more yolk in the first 48?h with no FD effect. When feed was made available, chicks from the FD group showed a large increase in small intestine weight relative to BW, surpassing (P? 4. Morphological measurements in all intestinal sections had higher values in chicks derived from the middle age breeder flock. FD to newly hatched chicks from the young breeder flock shortened villi (P?P? 5. Crypt depths were maximised between 7 and 14?d post-hatch in chicks from young and old breeder flocks, but crypt depths in chicks from the middle aged flocks continued to deepen.

6. The increased crypt depth may augment the number of enterocytes available for villus growth, and facilitate longer villi and greater villus surface area, in chicks from the middle age flocks. Intestinal morphological variation was associated with breeder flock age, which accounted for differential growth in chicks derived from young, middle, and old aged breeder flocks.     

Multi-carbohydrase enzymes improve feed energy in broiler diets containing standard or low crude protein

This study evaluated the effect of multi-carbohydrase (MC) on energy and nitrogen (N) balance and gene expression in broilers fed diets with different crude protein (CP) contents. The study employed a 2 × 2 factorial arrangement of treatments. The factors were presence or absence of MC, and standard (SCP) or low (LCP) dietary CP concentration. A 3-phase feeding program was used, including starter (0 to 7 d), grower (8 to 17 d) and finisher (18 to 28 d) phases. The study was undertaken in closed calorimetry chambers. Each of the 4 dietary treatments was replicated 8 times in total across 2 runs, with 2 birds per replicate (n = 64). Data for energy partitioning and N balance were collected from d 25 to 28. On d 28, birds were euthanized to collect muscle and intestinal tissue samples for gene expression. The results showed that the MC increased apparent metabolizable energy (AME, P < 0.01) and net energy (NE, P < 0.05), and reduced the feed conversion ratio (FCR, P < 0.01) in all diets. The proportion of energy retained as fat per total energy retention (REf/RE) was positively correlated with feed AME and NE (r = 0.541, P < 0.01 and r = 0.665, P < 0.001, respectively), suggesting that feed energy augmented with increased fat gain. Muscle ATP synthase subunit alpha (ATP5A1W) gene expression had a positive correlation with REf/RE and feed NE (r = 0.587, P < 0.001 and r = 0.430, P < 0.05, respectively). Similarly, muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1A) expression was negatively correlated with weight gain and positively correlated with FCR (r = −0.451, P < 0.05 and r = 0.359, P < 0.05, respectively). These correlations show that over-expressions of muscle genes related to energy production reduce bird performance. This study demonstrated that MC increase dietary energy utilization, regardless of dietary CP concentration. However, the energy released by the enzymes increases feed energy-to-CP ratio, meaning there is excess energy that is then deposited as body fat. This suggests that supplemental MC in broiler feeds is beneficial if diets are formulated to contain marginal energy levels.     

群体有益微生物饲料添加剂在肉鸡中的应用效果

将 1日龄艾维因肉仔鸡随机分为 2组 ,每组 5个重复 ,每个重复 5 5只鸡 ,共 5 5 0只鸡 ,进行 7周生长试验 ,研究应用群体有益微生物饲料添加剂发酵饲料后对肉鸡生产性能和经济效益的影响。试验结果表明 :饲喂群体有益微生物饲料添加剂发酵后的饲料 ,可显著降低后期料重比(P <0 .0 5 )和全期采食量 (P <0 .0 5 ) ,但不影响 7周末体重 (P >0 .0 5 ) ;在对肉品质进行多人品尝的试验中 ,75 %的品尝者认为 ,试验组鸡肉细嫩 ,味道鲜美。     

Effect of quantitative feed restriction on broiler performance

The objective of the current study was to determine the effect of quantitative feed restriction on the performance of broilers. A total of 270 unsexed broilers were randomly allocated to three treatments: with no feed restriction (T1), one week (T2) and two (T3) weeks of feed restriction from 22 days of age and then fed ad libitum until the age of 42 days. Treatments were replicated three times with 30 birds per replicate. Birds were fed with starter, grower and finisher diets. The feed consumed and body weights were recorded every week from the third to the sixth week. The average daily gain (ADG), average daily feed intake (ADFI) and the feed conversion ratio (FCR) were computed for each week. At Week 6, body weights of T3 birds were similar (P > 0.05) to those of T1 and T2 birds. There were also no treatment effects on the ADG at Week 6. In addition, no treatment effects (P > 0.05) were observed on ADFI at each stage of growth. Since ADFI and FCR were similar among the three groups, it was concluded that feed restriction by limiting the time to eat was not successful. There was also no evidence of compensatory growth in the restricted groups.     

早期限饲对肉仔鸡的影响

遗传育种选育和营养水平的改进,在使肉仔鸡生长速度不断提高的同时带来了一系列负面影响,如脂肪沉积、代谢性疾病、骨骼疾病、死亡率增加。早期限饲在改善这些问题上有一定的作用。本文综述了早期限饲对肉仔鸡的生产性能和健康状况等影响,并对早期限饲的进一步研究方向进行了展望。     

Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

Background: Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0-14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results: One-day-old broiler chicks were allocated to control (Con, ad libitum feeding), intermittent feeding (IF, feed provided on alternate days) and re-feeding (RF, 2 days ad libitum feeding after 12 days of intermittent feeding) groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor (IGF-IR) (P<0.05) and thyroid hormone receptor α (TRα) (P<0.05), and down-regulation of growth hormone receptor (GHR) (P<0.01) and IGF-I (P<0.01) mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher (P<0.05) and of TRα was lower (P<0.01) than in IF cells, suggesting that RF restored the mRNA expression of TRα and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group (P<0.05), indicating that RF reduced the pro-apoptotic influence of IF. Moreover, no significant effect of T 3 was detected on cell survival in IF cells compared with Con (P<0.001) or RF (P<0.05) cells. Conclusions: These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3 , and that RF partially reverses these effects. Thus, a moderate nutritional strategy for feed restriction should be chosen in early chick rearing systems.     

不同添加剂预混料配方对肉仔鸡生产性能的影响

添加剂预混料是配合饲料生产的核心和关键,其质量好坏直接影响配合饲料产品质量、动物生产性能以及动物产品的质量。笔者曾通过试验筛选出了添加剂的理想组合,本试验旨在通过对肉仔鸡生产性能的观察,探讨添加剂预混料的最佳配方,为实际生产中的广泛应用提供理论依据。1 试验材料与方法1.1 试验动物与分组 选用1日龄商品代艾维茵混合健雏360只,采用完全随机单因子设计分成4组进行试验。每组设3个重复,每重复30只（开始体重组间差异不显著,p>0.05）。试验期49d。     

Growth and development of the digestive organs and some enzymes in broiler chicks after hatching.

1. Body weight and the weight of the digestive organs and activities of some digestive enzymes were determined from hatching to 23 d of age. 2. Relative daily growth rate peaked at 11 d of age (22% gain/d) and then decreased gradually. 3. The vitelline residue was decreased rapidly from 4.6 g at hatching to negligible values from 4 d of age. 4. Maximal allometric growth of the pancreas and small intestine was 4-fold and that of liver 2-fold greater than that of the body. 5. Activities (units/kg body weight) of the digestive enzymes measured in the pancreas and intestinal contents increased with age. In the pancreas maximal values were attained on day 8 for amylase and lipase and 11 for trypsin and chymotrypsin. In the small intestine maxima were attained on day 4 for lipase, 11 for trypsin and chymotrypsin and 17 for amylase. 6. The development of secretion of digestive enzymes in the post-hatched chick could be a limiting factor in digestion and subsequently in food intake and growth.     

Effects of early and late feed restriction or feed withdrawal on growth performance,ascites and blood constituents of broiler chickens

A study was conducted with male broilers to determine the effects of early and late feed restriction or feed withdrawal. In the experiment five treatments were represented by three replicate floor pens, each containing 20 broilers. The experimental procedure was a completely randomized design. The treatments were ad libitum (AL), 25% (FR-25) and 50% (FR-50) feed-restricted or 8 h (FW-8) and 16 h (FW-16) feed withdrawal regimes, respectively. FW-16 regime significantly reduced weight gain to 21 days of age compared to AL or FR-25 regimes (P<0.05). However, the overall weight gains between 9 days and 42 days of age were not significantly affected by the treatments. FW-8 and FW-16 broilers consumed significantly less feed than either AL or FR broilers between 9 and 21 days (P<0.05), however FW-8 and FW-16 broilers had similar feed intake to AL or FR-25 and FR-50 broilers between 9 and 42 days of age. Feed: gain, abdominal fat pad and heart weights, mortality, death due to ascites, and the incidence of leg disorders were unchanged by feeding regimes, although the incidence of ascites in FW-16 was significantly (P<0.05) lower than AL fed broilers. Blood constituents, such as albumin, total cholesterol, ketone bodies, glucose, chlorine, lactate dehydrogenase, alanine aminotransferase and creatine were also significantly affected by feeding regimes (P<0.05).     

The effect of flavour on the growth and feed utilisation of broiler chicks

The results of four experiments testing the effect of a flavour made up of ethyl butyrate and other esters, phenylacetic acid and other organic acids, oil of juniper and other essential oils, diacetyl, and maltol on the feed utilisation and growth of broiler chicks to 8 weeks of age have shown small but consistent improvements in feed conversion. This improvement was significant (P>0.05) when the 8‐week results of the four tests were pooled, but were not significant when tested within each experiment. The 4‐week results of the combined experiments indicated a highly significant (P<0.01) improvement in feed utilisation following the use of the flavour.     

Methionine supplementation of low protein diets for broiler chicks in the tropics

1. In the first experiment, diets containing 14, 16, 18, 20, 22 or 24% protein with no methionine supplementation were tested, while in the second experiment diets containing 16, 18 and 20% supplemented with methionine to give 90, 100 or 110% of the recommended N.R.C. levels were compared with an unsupplemented 24% protein diet.

2. Methionine supplementation of the low protein diets stimulated faster gains than the unsupplemented diets but not enough to surpass the response to the 24% protein control diet.

3. It was concluded that a high protein diet unsupplemented with methionine was more economical to feed to broilers than supplemented low protein diets.     

寡肽在蛋白质营养中的作用及功能大豆寡肽蛋白饲料的开发

1传统蛋白质消化、吸收理论的局限性传统的蛋白质消化、吸收理论认为,蛋白质在肠道中最终都被消化成氨基酸,然后通过肠壁被机体吸收利用。根据这一理论,蛋白质仅为动物机体提供氨基酸,即蛋白质的营养就是氨基酸的营养。为使畜禽获得最佳生产性能,     

The development of a specific appetite for calcium in growing broiler chicks 1

1. Growing broilers were fed on a calcium‐deficient diet and allowed access to a separate calcium source.

2. When housed in a group, they consumed enough from the calcium source to supplement their diet adequately.

3. Caging individually inhibited the development of the calcium appetite in most birds even with visual contact between birds and colour cues to the calcium supplement.

4. Birds which had learned to consume a calcium supplement in a group continued to consume the supplement after being caged individually. Intake of the calcium source decreased immediately after the calcium‐deficient diet was replaced with one adequate in calcium, suggesting the existence of a physiological control mechanism for calcium intake.     

Comparative growth and development of the digestive organs and of some enzymes in broiler and egg type chicks after hatching

1. Body weight, the weight of digestive organs and activities of some digestive enzymes were determined from hatching to 14 d of age in meat‐ and egg‐type chickens.

2. Relative daily food intake and growth rate were much higher in meat‐than in egg‐type chickens. Relative daily food intake peaked at 30% of body weight at 3 d of age in meat‐type, and at 20% of body weight at 6 d of age in egg‐type chickens and then decreased gradually. The corresponding values for growth rate were 20 and 14%.

3. Allometric growth of the small intestine, intestinal contents and liver was greater in meat‐type chickens, but the growth of the pancreas attained a higher value in the egg‐type birds. Diminution of the vitelline residue was similar in the two breeds.

4. Pancreatic digestive enzyme activities were similar between stocks, but activities in the small intestinal contents were lower in meat‐type chickens.

5. The secretion of digestive enzymes in the newly‐hatched meat‐type chicken could be a limiting factor in digestion and, consequently, in food intake and growth.     

Starch digestion rates in multiple samples of commonly used feed grains in diets for broiler chickens

In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains (sorghum, wheat, maize, barley, triticale) were determined. The methodology to determine starch digestion rates in poultry is detailed herein. Starch digestion rates were not significantly different (P = 0.128) across the 18 feed grains, which reflects the wide variations that were observed within a given feedstuff. Nevertheless, starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0% (0.117 versus 0.075 min⁻¹; P = 0.012) than their sorghum-based counterparts on the basis of a pair-wise comparison. In descending order, the following starch digestion rates were observed: wheat (0.117 min⁻¹), barley (0.104 min⁻¹), triticale (0.093 min⁻¹), maize (0.086 min⁻¹), sorghum (0.075 min⁻¹). The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.