Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 50 num. 3 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Association of polymorphisms of vasoactive intestinal peptide and its receptor with reproductive traits of turkey hens</b>]]> The aim of this study was to identify variations of vasoactive intestinal peptide (VIP) and VIP receptor-1 (VIPR-1) genes that might be associated with turkey reproductive traits. One hundred twenty turkey hens were recorded for age at first egg (AFE), first egg weight (FEW), egg number (EN), total egg weight (TEW), laying period (LP), and broodiness. The DNA was isolated from blood samples and subjected to PCR amplification of the meleagrine VIP and VIPR-1 genes. The SNPs were detected by single-strand conformation polymorphism and the variant DNA fragments were sequenced. One mutation in 3'-UTR of VIP (G5846A) and two SNPs in intron 2 of VIPR-1 (C17687T and A17690T) were found, all of them novel. The associations of the three detected SNPs with the reproductive traits of turkeys were evaluated. The detected polymorphisms were used for marker-trait association analyses. The results of association analysis showed that G5846A on 3' UTR of VIP has a significant association with LP, EN, TEW, and AFE. The G allele of G5846A was the favourable SNP allele for LP, EN, and TEW traits. The AA genotype of A17690T on intron 2 of VIPR-1 was significantly associated with higher LP, EN, and TEW. AGAA haplotype showed association with higher EN and TEW. These results suggest that the SNPs in 3'-UTR of VIP and intron 2 of VIPR-1 genes may influence egg production traits in turkey hens. <![CDATA[<b>Antibiotic-free diet supplemented with live yeasts decreases inflammatory markers in the ileum of weaned piglets</b>]]> Emerging bacterial resistance to antibiotics increases the need for effective alternatives to control intestinal inflammation and thus gut disorders in piglets. This study evaluated the effects of including Saccharomyces cerevisiae (strain 1026) and Saccharomyces boulardii (CNCM I-1079) as antibiotic alternatives in the starter diets of pigs on the concentrations of ileal inflammatory markers (nuclear factor-KB (NF-kB)), interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-a), and interleukin-12 subunit p40 (IL-12p40), and villus height. Forty piglets were assigned to four experimental diets, namely basal diet (C-), basal diet with antibiotics (C+), basal diet with S. cerevisiae (Sc), and basal diet with S. boulardii (Sb). At 7 and 14 days post weaning, five piglets per diet group were euthanized to quantify the inflammatory markers and to measure villus height. The C- group exhibited the highest concentration of inflammatory markers and the most atrophied villi. The Sc group had intermediate values for both variables. The C+ group had the lowest values for inflammatory markers and the highest villus height was similar to that of the Sb group, which showed low concentrations of inflammatory markers, although not so low as those of the C+ group. Both yeasts could be used as antibiotic alternatives to reduce the use of antibiotics in pig starter diets. However, S. boulardii CNCM I-1079 supplementation controls inflammation and preserves intestinal mucosa more effectively than S. cerevisiae strain 1026. <![CDATA[<b>Genetic effects from an Afrikaner, Bonsmara, and Nguni three-breed diallel and top-crosses of Angus and Simmental sires</b>]]> Individual and maternal breed additive effects and heterosis exist for most economically important traits in cattle. Crossbreeding may therefore be valuable for emerging and commercial beef farmers in improving the productivity of their herds. Calves were produced by mating Afrikaner, Bonsmara and Nguni cows to Afrikaner, Bonsmara, Nguni, Angus and Simmental bulls. The cows used were from Vaalharts Research Station or were purchased from other herds. Data were collected over three years. Individual and maternal additive effects and individual heterosis were estimated simultaneously as continuous linear variates. The estimated genetic effects were then used to predict production levels that may be achieved through implementation of top-cross, two-breed rotation, and terminal sire crossbreeding systems. The individual estimates of the genetic effects were relatively small and in most cases were not different from zero, with the exception of the maternal additive effects of Nguni on preweaning traits and their individual additive effect on cow weight, which were less than those of Bonsmara. However, the alternative crossbreeding systems differed across traits. The straight-bred breeding system was least efficient, followed by the crisscross system (+2%) and the terminal sire system that utilized Simmental (+4%), with the terminal sire system utilizing Angus being on average most efficient (+8%). The inter-generational genetic differences in cow weight that resulted from the use of different breeds of sire increased its standard deviation by 5 to 6% in rotational crossing. Despite the relatively small magnitude of the genetic effects, advantages of crossbreeding systems became evident. <![CDATA[<b>Evaluation of three fast- and slow-growing chicken strains reared in two production environments</b>]]> The present study evaluated performance, physiological response and economics of commercial fast growing (CFG), commercial slow growing (CSG), and Rhode Island Red (RIR) chickens under intensive and free-range rearing environments. After 21 days of rearing under the same intensive environment 240 birds from each strain were subjected to free-range and intensive rearing until they were 56 days old. Each treatment was replicated six times with 20 birds in each replicate. Body surface and cloacal temperatures, respiration and heart rates, feed intake, bodyweight and weight gain, feed conversion efficiency, growth efficiency, and liveability were recorded. Significant differences among strains were detected in physiological response and growth performance (except liveability). Rearing environment also caused significant differences in physiological parameters (except body surface temperature) and growth performance (except liveability). Significant interactions of the strains and production systems were detected. The CFG strain grew most rapidly under the intensive system with differences between strains being reduced in the free-range system. The RSG and CSG strains had similar respiration rates under the two production systems but differed significantly from each other. However, the CFG strain had a significantly elevated respiration rate in the free-range system. Total input cost of rearing CFG under the intensive system was highest ($3.54) among the treatments, whereas CSG under a free-range environment generated the highest profit ($0.37 per bird). In conclusion, rearing CSG under free range was the most economic farming strategy in today's scenario. <![CDATA[<b>Use of phosphatidylcholine in Tris-based extender with or without egg yolk to freeze Bapedi ram semen</b>]]> Traditionally, egg yolk is a protective agent that is used to freeze semen in various species. However, the addition of egg yolk in extender risks the introduction of disease. Therefore, an alternative cryoprotective agent should be found to preserve ram semen. The aim of this study was to evaluate the effect of phosphatidylcholine (PC) as a protective agent in extender with or without egg yolk on semen characteristics and acrosome integrity of frozen then thawed Bapedi ram semen. Semen was collected from four mature Bapedi rams, in the Agricultural Research Council (ARC) Germplasm Conservation Programme, using an artificial vagina. Following collection, semen samples were randomly diluted into Tris-based extender (1: 2), with and without egg yolk, and supplemented with four concentrations of PC liposome (0 mg/ml), 0.25 mg/ml, 0.5 mg/ml and 0.75 mg/ml). Supplementation of PC liposome in extender with or without egg yolk did not improve the semen total motility (TM), progressive motility (PM) and rapid motility (RM) rate. The sperm cell membrane integrity in extender with or without egg yolk was not influenced by the supplementation of PC liposome after thawing (P >0.05). The addition of PC liposome to Tris-based extender with egg yolk had a similar result to control (Tris-based extender with egg yolk) on sperm cell acrosome integrity. In conclusion, supplementation of PC liposome to Tris-based extender without egg yolk had lower sperm cell viability and motility rates compared with the extender with egg yolk, regardless of concentration. <![CDATA[<b>Short Communication - Oxalate and silica contents of seven varieties of Napier grass <i>(Pennisetum purpureum)</i></b>]]> Oxalate and silica are considered antinutrients. Large quantities of oxalate and silica in plants can interfere with the uptake of essential minerals in ruminants. Therefore, the aim of this study was to compare the total silica and oxalate contents of seven varieties of Napier grass to find out which is best for cultivation. Taiwan, Zanzibar, Pakchong, Purple, Kobe, Indian, and Dwarf Napier grass were grown in a completely randomized design with three replications to determine their soluble oxalate, total oxalate, and silica contents. Plants were harvested at two months of plant maturity. Whole plant of the Dwarf Napier grass contained significantly higher soluble oxalate content than tall varieties. Total oxalate content in whole plant differed significantly among varieties. Dwarf showed the highest total oxalate content (3.23% dry matter (DM)) followed by Kobe (2.61%), Zanzibar (2.60%), Purple (2.44%), Taiwan (2.43%), Indian (2.15%), and Pakchong (1.95%). Regardless of variety, leaf tissue contained significantly higher soluble oxalate and total oxalate than stem tissue. There were no differences in silica content among them. In conclusion, the tall varieties could produce lower levels of soluble oxalate than the Dwarf variety, whereas silica content might not vary among them. <![CDATA[<b>Incorporating oldman saltbush hay and prickly pear in diets for red Sindhi calves</b>]]> This study was designed to evaluate the nutrient intake, digestibility, degradability, and ruminal characteristics of Sindhi heifers fed diets that contained a combined total of 75% oldman saltbush hay (hereafter saltbush hay) and prickly pear cactus. Eight 12-month old intact male red Sindhi calves (four fistulated and four non-fistulated) with an initial mean weight of 170 ± 5 kg were assigned to 4 * 4 Latin squares, where factors consisted of four diets, namely 15% hay and 60% cactus; 30% hay and 45% cactus; 45% hay and 30% cactus; and 60% hay and 15% cactus, and four times at which rumen fluid was collected. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes in kg/day and NDF in percentage live weight (LW), water intake, salinity, and conductivity increased with hay level. Intake and digestibility of non-fibrous carbohydrates were curvilinear with higher values in diets containing 30% saltbush hay. The apparent digestibility of dry matter (DM) and organic matter decreased linearly as the concentration of saltbush hay increased in the diet. The pH of the rumen fluid was within the acceptable range for favourable microbial growth. The low temperature and high salinity and conductivity indices in the diets should be viewed with caution at higher concentrations of saltbush hay, because of a possible decrease in nutrient absorption and the development of health problems in the animals. Apparent degradability coefficients of DM and NDF were affected significantly by inclusion of prickly pear and saltbush hay in the diets. <![CDATA[<b>Effect of arbuscular mycorrhizal inoculation on the quality and in vitro gas production of einkorn wheat straw</b>]]> The purpose of this study was to determine the effects of arbuscular mycorrhizal (AM) inoculation on the quality of einkorn wheat straw (EWS) and in vitro gas production (GP). It was found that AM inoculation of EW seed before sowing caused significant increases in crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), zinc (Zn), copper (Cu), and iron (Fe) levels of straw, and a (P <0.05) decrease in crude ash (CA), metabolizable energy (ME), and organic matter digestibility (OMD) compared with the straw of non-inoculated EW. The observed difference in the average GP among the between EWS from plants grown from inoculated seed and those from the untreated control was significant at all times between the third and 96th hour. However, when the GP kinetics of the groups was examined after 96 hours' incubation, only the difference in the gas amount of the easily soluble fractions of feeds was significant. The GP from the slowly fermented part, the GP rate constant and the potential GP of the straws were not affected by the AM inoculation (P &gt;0.05). Thus, inoculation of einkorn wheat with AM altered the nutritional value of the straw produced creating a roughage with decreased value for feeding ruminant livestock.