Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 49 num. 3 lang. <![CDATA[SciELO Logo]]> <![CDATA[<b>Probiotics as alternatives to antibiotics in treating post-weaning diarrhoea in pigs: Review paper</b>]]> The use of antibiotics to prevent post-weaning diarrhoea (PWD) in pigs has faced a setback owing to the associated antibiotic resistance in pigs and in the human populace that consumes the pork. In fact, antibiotic resistance that originates from the food chain is estimated to cause around 700,000 deaths globally each year. Consequently, scientists and researchers have suggested possible alternatives to antibiotics in pig diets. The chief of these has been the use of probiotics. The authors reviewed the literature on the use of probiotics as an alternative to antibiotics in treating PWD in pigs. It is clear that because of pathogenic Escherichia coli PWD continues to be a challenge to profitable swine production. The vast number of studies that was reviewed, point to the beneficial effects of probiotic supplementation on reducing the severity and incidence of PWD. However, some studies report inconsistencies to the general hypothesis. The majority of the microorganisms used as probiotics in the studies belong to the genera Lactobacilli, Bacillus, Bifidobacterium, Enterococcus, probiotic Escherichia coli, and Saccharomyces. The review also revealed that the bacterial strains that are used as probiotics are given individually or as combinations of multiple strains, and at various dosages, yielding varied results in each case. Interestingly, the authors observed wide disparities in the onset of probiotic supplementation and duration of the treatment to attain the results. Hence there is a need to standardize supplementation strategies, including dosage, onset and duration of treatment for probiotics. Furthermore, many of the in vivo studies that revealed positive effects of probiotics on diarrhoea and other production parameters were carried out in more controlled environments. The authors therefore suggest that more field studies in more natural and commercial farm settings should be conducted to augment the literature in relation to the use of probiotics as alternatives to antibiotics in treating PWD. <![CDATA[<b>Effect of betaine and ascorbic acid in drinking water on growth performance and blood biomarkers in meat ducks exposed to heat stress</b>]]> The aim of this study was to compare the effect of drinking water that contains various levels of ascorbic acid (AA) and betaine (BT) on growth performance and blood biomarkers in meat ducks exposed to heat stress. Six hundred and forty one-day-old Cherry Valley ducks were randomly assigned to one of seven treatment groups: i) control group, drinking water without ascorbic acid or betaine, ii) AA100, drinking water containing ascorbic acid at 100 milligrams per litre, iii) AA200, drinking water containing ascorbic acid at 200 milligrams per litre, iv) AA300, drinking water containing ascorbic acid at 300 milligrams per litre, v) BT400, drinking water containing betaine at 400 milligrams per litre, vi) BT800, drinking water containing betaine at 800 milligrams per litre, and vii) BT1200, drinking water containing betaine at 1200 milligrams per litre. The ducks were exposed to heat stress (11:00 to 17:00, 33 °C to 43 °C, relative humidity 70%, artificially controlled-environment houses) from the 22nd to 42nd days. Ducks from treatment groups AA300 and BT1200 displayed significantly increased bodyweight gains compared with those in the control group. Blood levels of glucose, and activities of aspartate aminotransferase and alanine aminotransferase in all treatment groups were significantly lower than those observed in the control group. Red blood cell count, platelet number, electrolytes and blood gas concentrations were significantly higher in all treatment groups compared with those in the control group. Blood pH levels in all treatment groups were lower than those in the control group. In conclusion, drinking water containing ascorbic acid or betaine improved the growth performance via biomarker homeostasis in blood of meat ducks exposed to heat stress. <![CDATA[<b>Ractopamine-induced changes in the proteome of post-mortem beef<i> longissimus lumborum </i>muscle</b>]]> Ractopamine is a beta-adrenergic agonist that is approved for use in beef cattle, pigs and turkeys as a repartitioning agent to increase lean muscle deposition and decrease lipogenesis. Although the effects of dietary ractopamine on the proteome profile of post-mortem pork muscles have been examined, its influence on beef muscle proteome has not been studied. Therefore, the objective of this study was to examine the effect of ractopamine on the proteome profile of post-mortem beef longissimus lumborum (LL) muscle. LL muscle samples were obtained from the carcasses of six (n = 6) steers fed ractopamine (RAC; 400 mg ractopamine hydrochloride for 28 days) and six (n = 6) steers fed no ractopamine (CON). The muscle proteome was analysed using two-dimensional gel electrophoresis and tandem mass spectrometry. Five differentially abundant spots were identified, and all the spots were over-abundant in RAC. The identified proteins were involved in muscle structure development (F-actin-capping protein subunit beta-2; PDZ and LIM domain protein-3), chaperone activity (heat shock protein beta-1), oxygen transport (myoglobin), and glycolysis (L-lactate dehydrogenase A chain). These results suggested that dietary ractopamine could influence the abundance of enzymes associated with muscle development and muscle fibre type shift in beef LL muscle. <![CDATA[<b>Effect of alternating total mixed ration and pasture feeding on the fatty acid content and health indices of Jersey and Fleckvieh x Jersey milk</b>]]> Certain fatty acids (FAs), such as omega-3 and conjugated linoleic acid (CLA) are considered essential FAs with beneficial health effects for humans. Milk is considered a relatively inexpensive and readily available source of these FAs and is part of a recommended healthy daily diet. The aim of the study was to determine the effect of diet changes on the FA composition of Jersey (J) and Fleckvieh x Jersey (FxJ) milk. Cows were alternately put on kikuyu-ryegrass pasture, followed by a feedlot system, then returned to kikuyu-ryegrass pasture for four weeks each. The same concentrate mixture was fed to cows regardless of feeding system. The feedlot system consisted of a partial total mixed ration (pTMR). Milk samples were collected two and four weeks after diet changes and stored at -20 °C until laboratory analysis by gas chromatography. The FA concentration of milk was not affected by breed, although it was affected significantly by diet changes. Most notably, the total omega-3 and -6 FAs decreased when cows were fed pTMR while increasing when the diet was changed back to pasture feeding. The CLA content of milk was similarly affected. That is, concentrations decreased significantly when the cows were on the pTMR diet and increased when cows were put back on the pasture-based diet. The results suggested that the health benefits of milk fat are affected negatively when cows are fed pTMR compared with being fed in a pasture-based system. The health benefits of milk are reduced owing to decreased levels of the CLA content of milk fat. Therefore, feeding additional hay in a pasture-based production system should be reconsidered when aiming to produce milk that provides health beneficial qualities. <![CDATA[<b>Effects of hourly, daily and seasonal variation of hazardous gases and climatic factors on the welfare of sheep housed in solid-floor confinement barns</b>]]> Ambient air quality in livestock buildings is one of the most important factors affecting environmental pollution and global warming. Carbon dioxide (CO2), methane (CH4), ammonia (NH3) and hydrogen sulphide (H2S) are among the most hazardous gases in terms of human and animal health. The aim of this study was to determine the effect of hourly, daily and seasonal variations in the levels of hazardous gases, such as CO2, CH4, NH3 and H2S in a solid-floor confinement sheep barn; as well as the effect of climatic parameters, temperature (T), relative humidity (RH) and air flow (AF) on animal welfare. The correlation between hazardous gases and climatic factors in the barn was also determined. The study was carried out on a sheep farm between July 2012 and June 2013 in Konya (Turkey) where few data are currently available on this subject. Climatic data were measured at intervals of five minutes at different points during this study, while hazardous gases were measured at the same intervals during the experimental periods (10 days for each season). All data were analysed by one-way analysis of variance (ANOVA) and Tukey's method was used to reveal intergroup differences. Cross-bilateral correlation between all data and different time periods was examined. There were significant differences between hourly and daily mean values of CO2, NH3, T, RH and AF. CO2 and NH3 levels showed a significant correlation with T and RH. Unfortunately, H2S and CH4 were below the level of detection in the study. Reducing the formation of these harmful gases, which have negative effects on animal production and cause environmental pollution, will be carried out with new sheep barn designs that take into account ambient air quality appropriate for animal welfare. <![CDATA[<b>Protease and phytase supplementation of broiler diets in which soybean meal is partially or completely replaced by raw full-fat soybean</b>]]> The nutrient composition and enzymatic in vitro nutrient digestibility of raw full-fat soybean (RFSB) were assessed prior to evaluating the influences of enzyme supplementation in diets in which commercial soybean meal (SBM) was partially (phase 1) or completely (phase 2) replaced by RFSB. A 2 x 2 + 1 arrangement was used in a two-phase feeding trial. In phase 1 (0 - 25 days) a positive control, commercial-type diet (PC), without RFSB or enzymes, and a negative control diet (NC), with 75 g RFSB/kg were used. The NC diet was supplemented with or without protease (0 or 15000 PRPOT/kg) and phytase (0 or 2000 FYT/kg). In phase 2 (26 - 31 days), RFSB (NC) or SBM (PC) was used as the sole source of crude protein (CP) for birds. Each treatment was replicated six times. Phases 1 and 2 had the same enzyme supplementation and treatment arrangements. The results showed that the concentration of trypsin inhibitors in RFSB as an ingredient was 16 564 TIU/g, and its CP in vitro digestibility was improved significantly by protease and protease plus phytase. Birds fed on PC and on NC plus protease and phytase finally consumed higher quantities of feed and had the highest bodyweight gain (BWG). Protease improved feed intake (FI), BWG and feed conversion ratio (FCR) by approximately 5.3%, 22.5% and 11.4%, respectively, in phase 2. Birds on the diet with protease plus phytase were 11.7% and 24.8% superior in BWG and FCR, respectively, to NC between 26 and 31 days. Supplementation with both enzymes reduced the weight of the pancreas. Supplementing NC with protease and phytase marginally improved the apparent ileal digestibility (AID) of protein and some amino acids (AA) at 25 and 31 days. Overall, BWG and feed efficiency of birds were improved by supplementation of both enzymes and, to a lesser extent, by protease on its own. <![CDATA[<b>Physical and mechanical characteristics of Hisex Brown hen eggs from three different housing systems</b>]]> The aim of this study was to compare physical and mechanical characteristics of Hisex hen eggs collected from three different housing systems: enriched cage housing, aviary housing, and free-range systems. The following physical and mechanical characteristics if eggs were compared: dimensions, surface area, volume, sphericity, shape index, shell thickness, weight, composition, yolk to albumen ratio, rupture force, specific deformation, absorbed energy, and firmness. The largest and heaviest eggs were collected from cage housing, followed by eggs from free-range systems and aviary housing. According to shape index, eggs from aviary housing can be described as round, while eggs from cage housing and free-range systems can be characterised as normal or standard. Eggs from free-range laying hens had the highest yolk percentage and yolk to albumen ratio (26.2% and 0.427). In comparison to eggs from aviary housing and free-range systems, eggs from enriched cage housing had the thickest shells and the highest shell strength, and required the highest force to rupture those eggs. The average force required to rupture Hisex Brown hen eggs from cage housing in all three axes was 44.14 N, which was 12.1% higher than the average force required to rupture eggs from a free-range system (39.37 N) and 17.1% higher than the average force required to rupture eggs from aviary housing (37.68 n). The highest forces required to rupture eggs from all three housing systems were determined on loading along the X-front axis and the lowest forces were determined along the Z-axis. The results obtained in this study can be useful to producers when selecting hen housing systems in order to reduce egg damage during storage and transport. <![CDATA[<b>Influence of low-tannin sorghum on performance and bone morphometries of male Ross 308 broilers aged 1 - 42 days</b>]]> The objective of this study was to determine the effects of low tannin sorghum as a maize replacement on the performance and bone morphometrics of Ross 308 broiler chickens. A total of 250 one-day-old broiler chickens were allotted to a complete randomized design with five treatments replicated five times. Birds were offered varying sorghum levels as maize replacement at 0% (control), 25%, 50%, 75% and 100%, formulated to be isonutritive and isoenergetic. The condensed tannin and total phenolic contents of the sorghum were analysed. Bodyweight and feed intake were measured weekly to calculate feed conversion ratio (FCR), and mortality was recorded as it occurred. Digestibility measurements were done when the chickens were between 15 and 21 days and between 35 and 42 days old. At ages 21 and 42 days, two chickens per pen were slaughtered to determine bone characteristics. A digital calliper was used to measure the length and diameter of the bones, and an electronic scale was used to determine the weight of the bones. Ash, calcium and phosphorus concentrations of the bones were determined. The Seedor and robusticity indices of the tibia were also calculated. The general linear model procedure of Statistical Analysis Software was used to analyse the data. At 1 - 21 days old bodyweight was higher for birds fed a level of 50% sorghum than those that were offered the control diet. Replacing maize with sorghum improved the metabolizable energy (ME) of broiler chickens aged 42 days. Bodyweight and FCR of birds fed diets with 50%, 75% and 100% sorghum were higher and better, respectively, than those on diets with 25% and 0% sorghum at 22 - 42 days old. Bone morphometries of chickens aged 1 - 21 days and 22 - 42 days were not affected by replacing maize with sorghum. Thus, maize can be replaced by a low tannin white sorghum without causing adverse effects on chickens. <![CDATA[<b>Responses of chemical composition, amino acid and fatty acid profiles of breast muscle to dietary crude fibre levels in China Micro-Ducks</b>]]> The effects of dietary crude fibre (CF) levels on the chemical composition, amino acid (AA) and fatty acid (FA) profiles of breast muscle in male China Micro-ducks (21 - 56 d) were investigated in this study. The birds were randomly allocated to four treatments, of which dietary CF levels were 16.7, 42.6, 77.9 and 101.6 g/kg of dry matter (DM), respectively. No influences on the proportions of crude ash, crude protein, lysine, methionine, threonine, phenylalanine, histidine, arginine, aspartic acid, glutamic acid, glycine, alanine, serine, cysteine, tyrosine, proline, C12:0, C18:0, C18:1n9, C20:0 and C22:1n9 in muscle were observed across the treatments. Consequently, the concentrations of semi-essential AA, non-essential AA, total AA, aromatic AA and delicious AA in muscle, along with the Δ-9-desaturase (18) index, were not affected by the treatments. Significant lower concentrations of valine, leucine, isoleucine, essential AA, branched-chain AA, C16:1n7 and monounsaturated FA in muscle, along with a lower ratio of branched-chain to aromatic AA, were noted in a dietary treatment with a CF level of 16.7 g/kg DM compared to other dietary treatments. The rise of the dietary CF level significantly increased the proportions of DM, ether extract, gross energy, C18:2n6, C18:3n3, C20:4n6, unsaturated FA, total FA, polyunsaturated FA, n-3 polyunsaturated FA, n-6 polyunsaturated FA, essential FA, and the Δ-9-desaturase (16) index. Furthermore, the rise of the dietary CF level increased the ratios of unsaturated to saturated FA, polyunsaturated to saturated FA, and n-6 to n-3 polyunsaturated FA in muscle. However, it decreased the atherogenic index and the proportions of C14:0, C16:0, and saturated FA significantly. In conclusion, depending largely on dietary levels, CF profoundly and positively influenced the nutritional quality of breast muscle, especially the FA profile.