Influence of dietary lactose on the gut flora of chicks

1. The gut microflora of chicks fed on a purified diet containing 300 g lactose plus 300 g starch/kg was compared with that of control birds receiving a diet containing 600 g starch/kg.

2. In 14‐d‐old conventional chicks, lactose in the diet decreased the incidence of lactobacilli and clostridia in the caecal contents, although when present in lactose‐fed chicks the counts of lactobacilli exceeded those of control chicks.

3. High counts of Proteus sp. were present in the caeca of control birds but they were completely suppressed in conventional birds fed on the lactose diet. In vitro tests showed that this inhibition was partially due to Escher‐ichia coli and Streptococcus faecalis.

4. The growth of Lactobacillus acidophilus was inhibited by lactose when gnotobiotic chicks were monoassociated but not when polyassociated. The protective effect was shown in vitro to be due to L. salivarius.

5. The pH was markedly lowered in the caecum of conventional and polyassociated chicks receiving dietary lactose. Of the strains used in gnotobiotic experiments E. coli, S. faecalis and L. salivarius produced the lowest pH values in the caeca.     

不同组方饲料添加剂在育肥猪中的应用研究

选用64头平均体重为(63.73±2.01)kg的杜长大育肥猪,按完全随机区组设计分为4组,每组4个重复,每个重复4头,各组猪分别饲喂含组方一、组方二、组方三复方添加剂的试验饲粮,研究不同组方添加剂对育肥猪生产性能、屠宰性能、肉品质及血液生化指标的影响,结果表明:与对照组相比,组方二能显著提高育肥猪的生产性能、屠宰性能,改善肉品质和生化指标。组方一能较好地提高生产性能和屠宰性能,并改善了生化指标,但效果不如组方二明显,对肉品质没有显著影响;组方三对以上4项指标影响均不显著,且后续的试验表明,该组方部分指标药物残留超标。     

添加剂对饲料品质和食品质量的影响

现代化畜牧生产不仅要以合理价格为广大消费者提供丰富的畜产品,还要重视食品质量,动物福利和环境保     

Studies on nitrogen metabolism in rats of different age fed on a protein-free diet. 2. The feed intake

Changes in the intake of dry matter (DM) of the protein-free diet (PFD) fed ad libitum were studied on male rats in relation to the shrunk body mass (SB) and duration of protein-free feeding (t). The intake of DM and changes of SB were investigated on the same rats and during the same experimental periods. The mean intake of DM in relation to PFD feeding periods t = 3, 6, 9, 12, 16 days and the daily DM intake (DMd) in relation to the daily shrunk body mass (SBd) were calculated on logarithmical values according to a model of linear regression y = a + bx and to a model of multiple regression y = b0 + b1x1 + b2x2. The rate of DM intake in relation to the duration of PFD feeding (t) did not differ significantly between age groups (k = 14) but the ak differed significantly. The common coefficient bc = 0.871 +/- 0.012 was less than 1***. This relationship is described by the equation: DM intake = Ak X t0.871, where: DM intake = the sum of intake in the periods of 3, 6, 9, 12 and 16 days (in grams), k = age group, t = PFD feeding period. No significant correlation (P less than 0.05) was found between bk and the initial body mass (SBi) or age of rats (r = -0.21 and -0.02, respectively) but between ak and SBi or age the correlation was highly significant (r = 0.960 and 0.832). This indicates that the amount but not the rate of DM intake depended on the initial body mass or age. The relation between DMd and SBd, the latter increasing with age but decreasing with the duration of PFD feeding, is described by equation: DMd intake = Ad X SBd0.503, where: DMd intake in grams, d = day 1 to 15 of PFD feeding, SBd = daily shrunk body mass in kilograms. The values of Ad decreased with the duration of PFD feeding. The using of multiple regression permitted to describe DMd intake as a function of SBd and (d) by a common equation: DMd intake = 27.02 X SBd0.503 X d-0.103; R = 0.976. Thus the daily DM intake was closely positively correlated with SBd and negatively correlated with the duration of protein-free feeding regardless of the age of rats.(ABSTRACT TRUNCATED AT 400 WORDS)     

Herbal feed additives containing essential oil: 1. Impact on the nutritional worth of complete feed in vitro

This study was taken up to assess the impact of supplementing herbal feed additives [HFAs; fruit of Myristica fragrans (Jayphall), seeds of Anethum sowa (Suva), fruit of Apium graveolens (Ajmo), fruit of Cuminum cyminum (Jeera), bark of Cinnamonum zeylanicum (Dalchini), or whole plant of Eclipta alba (Bhangro)] containing essential oils as active component on the nutrient utilization and methane production using wheat straw–based total mixed ration (TMR) as a substrate by in vitro gas production technique. The essential oil content was the highest (P < 0.01) in M. fragrans followed by E. alba and A. sowa. In addition to essential oils, these HFAs also contained saponins, tannins, and antioxidants. The HFAs were supplemented at 1–3% of substrate dry matter (DM). The data were analyzed by 6 × 4 factorial design. Irrespective of level of HFA, the net gas production (NGP) and metabolizable energy (ME) availability was the highest (P < 0.01) in TMR supplemented with C. zeylanicum comparable with E. alba, but higher than TMR supplemented with other HFAs. Supplementation of TMR with different HFAs did not affect the digestibility of neutral detergent fiber (NDF) and true organic matter (TOM) and partitioning factor (PF). The total volatile fatty acids (VFAs), acetate, propionate (P < 0.01), and butyrate (P < 0.05) production was the highest in TMR supplemented with A. sowa, and the lowest was observed in TMR supplemented with C. cyminum. The isobutyrate and valerate production was also the highest (P < 0.01) in diet supplemented with A. sowa, but isovalerate production was the highest (P < 0.01) in diet supplemented with C. zeylanicum. The A:P ratio was the best in TMR supplemented with A. sowa. The efficiency of rumen fermentation was the highest, and efficiency of conversion of hexose to methane was the lowest in diet supplemented with A. sowa as compared to all other supplements. The in vitro methane production expressed as either percent of NGP, ml/100 mg DM of substrate/24 h, or as ml/100 mg of digestible OM/24 h was the lowest in TMR supplemented with A. sowa. The ammonia nitrogen production from TMR supplemented with M. fragrans and A. sowa was comparable, but significantly (P < 0.01) lower than TMR supplemented with other HFAs. Irrespective of the nature of HFA, the NGP and ME availability were significantly (P < 0.01) higher in TMR supplemented with HFAs at all levels as compared to un-supplemented TMR. As compared to control, the digestibility of NDF and that of TOM was depressed slightly in all the HFA-supplemented TMRs. The supplementation of HFAs at 2% of substrate DM improved (P < 0.01) the production of total VFAs, acetate, and propionate, and that of isovalerate in comparison to the un-supplemented TMR. The acetate to propionate ratio increased (P < 0.01) with the increase in the level of supplementation of HFAs containing essential oils. The methane and ammonia productions were depressed significantly when TMR was supplemented at 2% level of HFAs as compared to control TMR. It was concluded that supplementation of TMR with A. sowa at 2% of substrate was fermented better as indicated by the production of total and individual VFA, methane, and ammonia as compared to TMR supplemented with other HFA or un-supplemented TMR.

     

Studies on nitrogen retention in growing pigs

Nitrogen retention (RN) was measured in 60 barrows of Danish Landrace and a total of 470 balance periods was carried out during the growth period from 20 to 85 kg live weight. In the first serie (Expt A) six different feed compounds of high biological value (HBV) were fed to 48 barrows, while in the second serie (Expt B) 12 barrows were measured on feed compounds of HBV or low biological value (LBV). Three different levels of gross energy were used in Expt B. Individual differences of 10-20% in the pigs capability for nitrogen retention were observed. Nitrogen retention increased from 12 to 21 g N/d on the HBV-compounds and was not influenced by increasing nitrogen or energy intake. Nitrogen retention was curvilinear in relation to metabolic live weight (kg0.75) in both series. A parabolic function on kg0.75 gave the best fit to the data with the following regression equations: Expt A + B: RN, g/d = 1.48 LW, kg0.75 - 0.027 LW, kg1.50 (HBV) Maximum = 20.5 g RN/d at 84 kg LW Expt B: RN, g/d = 1.03 LW, kg0.75 - 0.013 LW, kg1.50 (LBV) Maximum = 20.4 g RN/d at 133 kg LW     

Feed-and feed additives-related aspects of gut health and development in weanling pigs

The development of new/different management and feeding strategies to stimulate gut development and health in newly-weaned pigs, in order to improve growth performance while minimizing the use of antimicrobial compounds such as antibiotic growth promotants (AGP) and heavy mineral compounds, is essential for the long-term sustainability of the pig industry. Factors including the sub-optimal intake of nutrients and energy, inappropriate microbiota biomass and (or) balance, immature and compromised immune function, and psychosomatic factors caused by weaning can compromise both the efficiency of digestion and absorption and intestinal barrier function through mucosal damage and alteration of tight junction integrity. As a consequence, pigs at weaning are highly susceptible to pathogenic enteric conditions such as post-weaning diarrhea that may be caused by serotypes of enterotoxigenic Escherichia coli. Many dietary components, e.g., protein, fiber, feed additives and minerals, are known to influence microbial growth in the gastrointestinal tract that in turn can impact upon pig growth and health, although the relationships between these are sometimes not necessarily apparent or obvious. In a world climate of increased scrutiny over the use of antibiotics per se in pig production, certain feed additives are seen as alternatives/replacements to antibiotics, and have evolved in some cases to have important roles in everyday commercial pig nutrition. Nevertheless and in general, there remains inconsistency and variability in the efficacy of some feed additives and in cases of severe disease outbreaks, for example, therapeutic antibiotics and/or heavy minerals such as zinc oxide (ZnO) are generally relied upon. If feed ingredients and (or) feed additives are to be used with greater regularity and reliability, then it is necessary to better understand the mechanisms whereby antibiotics and minerals such as ZnO influence animal physiology, in conjunction with the use of appropriate challenge models and in vitro and in vivo techniques.     

不同绿色添加剂组合对生长育肥猪生产性能的影响

试验选择90头平均体重为（18.7+2.1）kg的杜×长×本三元杂交断奶仔猪,按单因子随机试验设计分为3组,每组3个重复,每个重复10头仔猪进行试验。对照组饲喂基础日粮+10mg/kg速大肥;试验1组饲喂基础日粮+0.1％生命素+0.05％迈克活菌酶;试验2组饲喂基础日粮+200mg/kg糖萜素+0.03％迈克活菌酶+0.05％。生命素。各组基础日粮完全相同。结果三组供试猪的平均日增重分别为670.25,667.83和647.08g（P>0.05）,料重比分别为3.23,3.09和3.11（P<0.05）,扣除实际耗料成本,每头猪实际赢利分别为97.26,92.90和93.77元,两试验组的生物学综合评定值分别为104.17和 101.86。     

Influence of spiced feed additives on taste of hen's eggs

The effect of the spices garlic (Allium sativum), extract from garlic, sage (Salvia officinalis), caraway (Carum carvi), peppermint (Mentha piperita), fennel (Foeniculum vulgare), thyme (Thymus vulgaris), paprika (Capsicum annuum), marjoram (Majorana hortensis), cardamom (Elettaria cardamomum) and sausage-mix fed to white hybrides on the quality of eggs (n = 705) was tested by 10 qualified persons. Changes in smell or taste were partly significant; a direct improvement is hard to induce. A well seasoned taste was obtained by feeding of garlic, fennel, peppermint and marjoram. They produce an aromatic flavor. A practical application is possible but limited by higher production prices. Further, it is uncertain if there is a need for "taste-manipulated" eggs.