Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 48 num. 5 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Effect of dietary rape seed meal on growth performance and meat quality of growing-fattening pigs</b>]]> The objective of this research was to evaluate the nutritive value of rapeseed meal (RSM) as a protein source for pigs, and the effect of graded inclusion levels of RSM as a replacement for imported soybean meal (SBM) on growth performance and carcass quality of pigs. Two trials were conducted, a digestibility trial, and a growth performance trial. In the digestibility trial, which lasted 38 days, four castrated male Large White χ Landrace pigs with an initial bodyweight of 40.3 ± 2.4 kg were used. Digestible energy (DE) per kg of RSM, digestibility energy of RSM and the apparent digestibility coefficients (%) of RSM nutrients were assessed by the method of difference. A total of 64 (Large White χ Landrace) pigs with average initial bodyweight of 11 ± 1.3 kg were used in the growth performance trial. The experiment lasted 15 weeks, and was divided into three growth stages. The RSM was added to the pig diets at levels from 1% to 21%. The dietary level of glucosinolates (GLS) ranged from 0.149 μmοΙ/g to 3.129 μmοΙ/g and RSM replaced from 3.4% to 100% of the SBM in the diets. It was proven that up to 15% of RSM of Greek origin with a GLS content of 14.9 μmοΙ/g could be used in nutritionally balanced diets as an alternative to imported soybean meal for growing-finishing pigs, as it provides economic benefits and has positive effects on growth performance and carcass quality. <![CDATA[<b>Prediction of <i>in vivo </i>organic matter digestibility of ruminant feeds using <i>in vitro </i>techniques</b>]]> Prediction equations derived from in situ and in vitro analytical techniques to determine in vivo organic matter digestibility (OMD) are useful tools to estimate the quality of livestock feed. Most derived equations are aimed at groups of feedstuffs (forages or concentrates) or feeds separately. In this study of OMD, the prediction equations of the modified two-stage Tilley & Terry in vitro technique (MT) and pepsin-acid multi-enzymatic technique (PME) are compared, validated, and improved in relation to verified in vivo results using feedstuffs and complete diets. Initial comparison with in vivo data showed that the combined dataset and that of single feedstuffs achieved acceptable R² values for both MT and PME (0.88 and 0.92, 0.87 and 0.89, respectively). The validation with the second dataset established that the initial equations were valid with R² values of 0.96 for MT and 0.91 for PME on the combined feeds dataset. The establishment of a prediction equation using both datasets resulted in improved R² values over the initial equation. With combined feeds using MT it was 0.94, compared with 0.88, and using PME, it was 0.91 compared with 0.87. No significant decrease occurred in the variation of OMD between the datasets, as explained by the model when omitting on separate slope and intercept, thus confirming2 the same population assumption. The data sets could be combined for a new prediction equation. The R values were 0.94 and 0.91 for MT and PME methods for combined feeds, respectively. The new improved in vivo prediction equation in each instance was thus valid and a true improvement on the initial prediction equations. The PME method can be used for predicting OMD as it negates the use of rumen liquor and confidently replaces MT OMD determinations. <![CDATA[<b>Effect of <i>Vachellia erioloba </i>and <i>Dichrostachys cinerea </i>pod supplementation on performance of does and kids of Namibian Caprivi and Ovambo indigenous goats</b>]]> An on-station feeding trial was conducted to determine the effects of Vachellia erioloba (VE) and Dichrostachys cinerea (DC) pod supplementation on intake, doe weight changes and growth of kids. Forty-two indigenous lactating does with average weight of 35 ± 0.5 kg from Parities 2 to 4 and grouped by ecotype (Caprivi and Ovambo) were allocated to a 2 x 3 factorial arrangement of treatments in a randomized complete block design with six does per treatment. The main factors were two pod types (VE, DC) at three feeding levels (20%, 40%, 60%), benchmarked against positive control (commercial feed (COM)) resulting in seven treatment diets. Phosphate salt lick and water were available ad libitum. Data were analysed as repeated measures using Proc Mixed (SAS, 2008). Voluntary feed intake (VFI) increased steadily for all treatments, peaking at about Week 5, followed by a drop, and then gradual stabilization in Weeks 7 to 12. Intake of does dropped drastically with VE60 and DC60 diets. Does in Parity 3 had significantly higher VFI than those in Parity 2, but there were no differences with Parity 4 does. Does in Parities 3 and 4 were significantly heavier than those in Parity 2. Doe weights declined from Week 1 to Week 8 and then increased gradually. Male kids were heavier than female kids (13.3 ± 0.2 vs. 10.5 ± 0.1 kg). The regression of kid weights on age (days) was 0.030 ± 0.012. Kids from does in Parities 3 and 4 had significantly higher weights than those from does in Parity 2. Single kids were heavier than twins (13.3 ± 0.2 vs.10.5 ± 0.1 kg). Kid weights from does supplemented with DC20 were similar to those receiving COM, VE20 and VE40, but kid weights of does supplemented with VE60, DC40 and DC60 were inferior to other treatments. Supplementing lactating goats with pod-based diets, particularly V. erioloba at 40%, may lead to increased VFI, reduced bodyweight loss in does and increased kid pre-weaning weights. <![CDATA[<b>Phenotypic and genetic characterization of indigenous Tswana goats</b>]]> Tswana goats that were kept in communal systems in three agro-ecological regions in Botswana were characterized according to phenotypic measurements and genotypic data. Objective measurements for 123 goats included bodyweight (BW), body length (BL), heart girth (HG), height at withers (HW), and tail length (TL), while qualitative traits included coat colour and presence or absence of horns and beards. Age was estimated based on dentition. Hair samples were collected from 48 of the phenotyped animals in the largest region (central region) and genotyped with the Illumina Goat50K SNP chip. Mixed coat colour was predominant and across regions 95% of the goats were horned and bearded. Goats in the northwest region had the lowest BW and significantly higher HG values in all age groups compared with other regions. Goats over four years old in the central and northwest regions were significantly longer in body compared with the ones from the southern region. The average expected heterozygosity and inbreeding coefficient were 0.423 ± 0.03 and 0.009 ± 0.05, respectively. Principal component analysis clustered most animals, with a few outliers. The effective population size has decreased over time and at 13 generations ago was estimated at 266. There were high genetic and phenotypic variations in the indigenous Tswana goats, which should be exploited to increase performance through within-breed selection and structured crossbreeding. <![CDATA[<b>Serum biochemical profile of two broiler strains supplemented with vitamin E, raw ginger <i>(Zingiber officinale) </i>and L-carnitine under high ambient temperatures</b>]]> In this study, the authors evaluated the comparative effects of dietary supplementation of ginger (Zingiber officinale), vitamin E and L-carnitine on certain blood parameters of two strains of broilers in summer. A total of 320 broiler chicks (Hubbard and Cobb) were divided into two groups. The two groups were subdivided into four subgroups with four replicates with '0 chicks per replicate. In each strain subgroup was kept as control while other subgroups were provided with ginger (2%), L-carnitine (500 mg/kg) or vitamin E (250 mg/kg) in the basal diet up to 42 days old. Supplementation of the diet with vitamin E, ginger and L-carnitine significantly decreased mean cholesterol, alanine aminotransferase (ALT), glucose, triglyceride, low density lipoprotein (LDL), and increased high density lipoprotein (HDL) and serum protein concentrations. The results of vitamin E were comparatively better than those of the other two feed additives. The blood biochemical parameters did not vary between the broiler strains. From the findings of the current study, it was concluded that high ambient temperature had a negative effect on broiler hepatic and lipid profiles, and the supplementation of diets with vitamin E, ginger and L-carnitine improved broiler blood biochemical parameters. <![CDATA[<b>Characterization of seminal plasma constituents of unimproved indigenous and Tankwa goats</b>]]> The aim of the study was to characterize and compare seminal plasma constituents of unimproved indigenous and Tankwa goats. In this study, unimproved indigenous (11) and Tankwa (11) goats were used. Their average age was 3 ± 0.8 years and average bodyweights were 35.5 ± 2.1 kg and 59.8 ± 1.9 kg, respectively. Semen samples were collected with an electro ejaculator, and evaluated for macroscopic and microscopic semen characteristics and seminal plasma constituents. Both unimproved indigenous and Tankwa goats had normal semen characteristics for goats, with the exception of sperm cell concentration. However, Tankwa goats had higher straight-line velocity and average path velocity compared with unimproved indigenous goats. Unimproved indigenous goats had higher intact acrosome than Tankwa goats. Lipocalin-type prostaglandin-D synthase was one of the constituents that were detected, but it was below the detection limit of 0.5 mmol/L. Moreover, the semen of unimproved indigenous and Tankwa goats had the same levels of fertility-associated antigen, lactate dehydrogenase, sodium, potassium, magnesium, calcium, glucose, cholesterol, triglyceride, lipids and urea. In conclusion, unimproved indigenous and Tankwa goats had the same seminal plasma constituents. These constituents seem to be optimal for the sperm cells, as they resulted in acceptable semen characteristics, except for sperm cell concentration, which was low. Moreover, acceptable standards need to be set for all seminal plasma constituents, as they are not currently known. <![CDATA[<b>Diurnal ingestive behaviour of steers grazing Alexander grass with various levels of nitrogen and feed supplements</b>]]> Given the increasing availability of new cultivars with high yield potential, the use of annual tropical forages to improve cattle production systems is increasing and therefore warrants more research. The objective of this study was to quantify the influence of feed supplementation and nitrogen fertilization on the diurnal ingestive behaviour of crossbred steers (zebu x taurine), maintained on a pasture of Alexander grass (Urochloa plantaginea). The treatments included the application of nitrogen fertilizer at 100 kg/ha; at 100 kg/ha + supplemented feed of wheat bran (0.5% of bodyweight); and at 200 kg/ha. The study used a completely randomized design with three replications. The paddock size was 0.7 ha. Data were analysed by fitting mixed models. The times spent resting, ruminating and consuming water were not different among treatments. However, time spent grazing significantly differed. On average, steers given supplemented feed spent less time grazing (297 min/day) than steers without the supplemented feed (345 min/day). Steers in the pasture with supplementation showed a significantly greater number of daytime bites (2029 bites) than steers in the 200 kg nitrogen treatment (1715 bites). Supplementation reduced grazing time without altering other behaviour variables. The number of daily bites was lower on the pasture with the higher nitrogen level. <![CDATA[<b>Effects of various levels of organic acids and of virginiamycin on performance, blood parameters, immunoglobulins and microbial population of broiler chicks</b>]]> This experiment was conducted to investigate the effects of various levels of organic acids and virginiamycin on performance, blood parameters, immunoglobulin and microbial population of broiler chickens. This trial was conducted in a completely randomized design using five treatments and four replicates. The dietary treatments included a control diet without additives, diets containing 0.05%, 0.10% and 0.15% mixtures of organic acids, and a diet containing virginiamycin as an antibiotic. Based on the results, there was no significant effect of the experimental diets on feed intake of the broilers during the starter period. However, at the end of the grower period and throughout the rearing period, feed intake was significantly improved by experimental dietary treatments. Moreover, diets including organic acids enhanced the microbial population of broiler gut. Thus, the current findings support the conclusion that organic acids improve productive traits and health status in broiler chickens. <![CDATA[<b>Influence of dietary supplementation of probiotics on intestinal histo-morphometry, blood chemistry and gut health status of broiler chickens</b>]]> The objective of this experiment was to investigate the effects of dietary supplementation of probiotics, Lactobacillus acidophilus and Bifidobacterium bifidum, on histo-morphologic measurements of the small intestine and on the gut health status of broiler chickens. A total of 240 day-old broiler chicks were randomly assigned to one of six dietary treatments for six weeks. The dietary treatments were basal diet (T1); basal diet + bacitracin methyl di-salicylate (BMD) at 20 mg/kg diet (T2); basal diet + L. acidophilus (10(6) and 10(7) cfu/gm diet) (T3 and T4); and basal diet + B. bifidum (10 and 10 cfu/gm diet) (T5 and T6), respectively. The villus height (VH), width (VW), crypt depth (CD) and the ratio between villus height and crypt depth (VH: CD) were significantly increased at 21 days and 42 days in L. acidophilus-supplemented groups (T3 or T4). No significant differences were observed in protein, albumin and serum mineral (Ca and P) concentrations and alkaline phosphatase (ALP) activity in any of the dietary probiotic treatment groups. Aspartate aminotransferase (AST) and creatinine concentrations were increased, whereas alanine aminotransferase (ALT), uric acid and total cholesterol levels were significantly decreased in probiotic-supplemented groups. Coliforms and total anaerobes counts were significantly reduced at 21 and 42 days at the ileum and caecal in T4, whereas the lactic acid bacteria (LAB) Lactobacilli count was significantly increased in all the probiotic-supplemented groups. The results of the present study indicate that L. acidophilus at 10(6) cfu/g feed inclusion in basal diet may improve blood biochemical parameters and histo-morphometry in the intestine and gut health in broiler chickens, resulting in a valid feed additive to replace antibiotic growth promoters. <![CDATA[<b>Feeding preferences of ostriches towards the inclusion of full-fat canola seed in grower diets</b>]]> The largest expense of an intensive ostrich production unit is feed cost (ca.75%). Protein makes up a great portion of feed for monogastric animals and this expense can be lowered by utilizing locally produced feedstuffs such as full-fat canola, although it is not clear whether ostriches will readily consume full-fat canola because of its anti-nutritional and other known factors. To evaluate the feeding preference of ostriches towards full-fat canola, 60 South African Black ostriches (82.2 ± 1.06 kg in live weight) were placed in 10 camps of six birds per camp. Each camp had five identical feed troughs containing diets in which full-fat canola seed (FFCS) incrementally (0, 25, 50, 75 and 100% of protein source) replaced the soybean oilcake meal (9.8% of the total diet composition in control diet was soybean oilcake meal and full-fat canola was included up to 27.5% of the total diet) as protein source. Dry matter intake (DMI) was measured daily and feed colour characteristics were measured, based on L*, a* and b* colour attributes. Only the 25%FFCS showed a higher DMI (817.38 ± 81.98 g/bird/day) and percentage DMI (-29.53°%) than the other diets, with an average DMI of 488.8 g/bird/day) and percentage DMI of 17.62%. Although the 0%FFCS, 50%FFCS and 75%FFCS had a lighter colour than the 25%FFCS and 100%FFCS and the b* colour parameter for 100%FFCS was lower than the rest, it is believed that these differences had no effect on DMI. Based on the results of this study, diets with up to 27.5% full-fat canola seeds had no detrimental effect on feed intake of finishing ostriches. Birds prefer diets with a combination of 6.9% full-fat canola seed and 7.4% soybean oilcake meal. <![CDATA[<b>Impacts of red pepper supplemented diets and different storage conditions on eggs obtained from free-range laying hens</b>]]> Egg quality depends on many conditions, including diet and storage temperature. Consumers usually assess it by checking yolk colour. The aim of the study was to indicate the effects of storage periods (7, 14 and 21 days) and temperature (room and refrigerator) on egg quality parameters, especially yolk colour. The experiment was carried out with 150 eggs, which were collected from free-range Lohmann brown laying hens (42 weeks old) fed with or without 0.75% red pepper supplemented diets. The highest weight loss was observed in the eggs stored at room temperature (23 °C, 64% humidity) for 21 days. In addition, it was discovered that the highest air cell height (ACH) was detected in the eggs stored at room temperature for 14 and 21 days. Red pepper supplementation and storage time and temperature were found to have been effective on the Roche yolk colour fan values (RYCF), lightness (L*) and yellowness (b*). Additionally, red pepper supplementation had a significantly positive effect on the redness (a*) value of the yolk. However, no statistical difference in the a* value was determined between the fresh eggs and the stored eggs supplemented with red pepper. The supplementation of 0.75% red pepper as a natural colouring agent to the diets of free-range laying hens had a positive effect on the yolk colour, which is an important attribution for consumer perception. Furthermore, the colours of the yolks of eggs stored in the refrigerator for a week were not significantly different from the fresh ones. Consequently, the present study suggests feeding laying hens diets supplemented with 0.75% red pepper might be useful in improving yolk colour. The results indicate that the eggs stored in the refrigerator might be closer to the characteristics of fresh eggs. In contrast, eggs stored at room temperature showed more deterioration between treatments.