Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 45 num. 4 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Variability in ejaculation rate and libido of boars during reproductive exploitation</b>]]> The main objective of the study was to evaluate variability in the ejaculation rate and libido of boars under various genetic and non-genetic influences. A total of 7171 semen samples were collected from Swedish Landrace, Large White and Duroc boars reared under commercial production conditions. Time spent in preparing or collecting, constituted the period from the entry of boars into the room for collecting semen to onset of ejaculation. Ejaculation rate was defined as the volume of sperm extracted (mL) per unit of time (min). The index of boar libido was defined as the relationship between productive (duration of ejaculation) and unproductive (time spent in preparing to collect/jump) periods. Average values of the interval between two collections, age of boar at collection, time spent in preparing for collection, duration of ejaculation, volume of ejaculate, rate of ejaculation and libido index were: 8.83 days, 551.2 days, 3.56 min, 6.06 min, 231.9 mL, 37.67 mL/min and 1.76, respectively. Ejaculate traits and libido varied according to breed, season and collector, with the exception of seasonal variability of duration of ejaculation. The regression effect of the interval between two collections of ejaculate and age of boar at collection was not statistically significant only for duration of preparing for collection. Unlike the ejaculation rate, during the summer and autumn periods, boars exhibited weaker libido than in winter and spring. Duroc boars were inferior to the fertile breeds (Swedish Landrace and Large White) in terms of shorter duration of ejaculation, lower volume, lowest rate of ejaculation and weakest libido. Variability of rate of ejaculation and of boar libido indicates the need to include these traits in breeding programmes and the possibility of improving these traits. <![CDATA[<b>Intestinal morphology, digestive organ size and digesta pH of broiler chickens fed diets supplemented with or without <i>Moringa oleifera </i>leaf meal</b>]]> The intestinal morphology and pH of digesta of broiler chickens at 35 days old were studied. Birds were reared on these dietary treatments (T). T1, positive control, contained 668 g salinomycin and 500 g zinc bacitracin per kg of feed. Treatments, T2, T3 and T4, contained graded levels of Moringa oleifera leaf meal (MOLM) per kg of feed, namely starter (1, 3, 5 g), grower (3, 9, 15 g) and finisher (5, 15, 25 g). T5 was a negative control (without supplementation). Birds were provided feed and water ad libitum. Birds in T3 had the highest proventriculus digesta pH, and T5 birds the lowest. Birds that were supplemented with MOLM -and surprisingly those from the negative control - had significantly higher caecal digesta pH, while T1 had the highest ileal digesta pH. Duodenal villous length was longest in T2, and shortest in T4. Jejunal villous length was longest in T3 and shortest in T2 birds. T3 and T4 jejunal villi were widest, with T1 birds having the shortest. Ileal villous was longest in T2 and T5 birds, while T3 birds had the shortest. Duodenal surface area for absorption was larger in T2 and T5, and smaller in T4, while T3 had the largest ileal surface area, and T1 the smallest. The jejunal surface area was largest in T3 (53.2) and T4 (50.7), and smallest in T1 (25.0). The current results reveal a regulatory effect of MOLM on the gastrointestinal tract, which could be attributed to the coarseness of the diets, thus raising the pH and resulting in thicker digesta viscosity, which is a clear sign of a healthy gut. <![CDATA[<b>Effects of coriander <i>(Coriandrum sativum </i>L.) seed powder and extract on performance of broiler chickens</b>]]> This study was conducted to investigate the effects of different levels of coriander (Coriandrum sativum) seed powder and extract on the performance and carcass characteristics of broiler chickens. A total of 420 day-old broiler chicks (Ross 308) were allocated randomly into seven treatments of 60 birds per group. Each treatment had four replicates (15 chicks per replicate). The trial was designed with seven treatments, consisting of a control diet without coriander, this is, the control group (CG); three treatments, which included the control diet plus three levels of coriander extract in water (750, 1000, and 1250 mg/kg); and the another three, which received the control diet plus three levels of coriander powder (1.5%, 2.0% and 2.5%). Performance parameters were monitored throughout the experimental period. At 21 - 42 d old, the inclusion of 952 mg/kg of coriander extract in drinking water maximized weight gain, while the feed intake of the experimental period (1 - 42 d) was maximized at the coriander powder level of 1.2%. Feed conversion ratios improved with the inclusion of coriander powder in the diet throughout the experimental period. These results suggest that coriander powder in the diet and coriander extract in water could replace synthetic antibiotics and could be regarded as natural feed additives and growth promoters in poultry diets. <![CDATA[<b>Reproductive performance of Jersey and Fleckvieh x Jersey heifers and cows maintained on a pasture-based feeding system</b>]]> Crossbreeding is regarded as a faster way than using pure dairy breeds to improve the reproductive performance of dairy cows, which is pivotal to farm income. The reproductive performances of Jersey and Fleckvieh x Jersey (F x J) heifers and cows were compared in a pasture-based production system. Heifers were inseminated when showing signs of heat from 13 months old and cows from 40 days post calving. Using insemination records and pregnancy check results, fertility traits were derived and compared between breeds, using analysis of variance for continuous records. Age at first insemination and conception age for heifers did not differ between the two breeds, resulting in a similar age at first calving. For cows, the mean (± SE) interval from calving to first insemination was shorter for F x J cows, being 76.7 ± 2.2 days compared with 82.4 ± 2.5 days for Jersey cows. A larger proportion of F x J cows were inseminated within 80 days post calving, compared with the Jersey cows (0.70 and 0.54, respectively). Furthermore, the proportion of cows confirmed pregnant by 100 days in milk was higher for F x J cows in comparison with Jersey cows, being 0.79 and 0.66, respectively. Although the absolute number of days between calving and conception (days open) was slightly less for F x J cows in comparison with Jersey cows (104.8 ± 6.8 and 114.8 ± 8.1 days, respectively), the difference was not significant. These results indicate the potential of improving reproductive performance of Jersey cows through crossbreeding with the dual-purpose Fleckvieh. <![CDATA[<b>Fatty acid composition of beef steers as affected by diet and fat depot</b>]]> Subcutaneous and perirenal fatty acid (FA) profiles were compared in steers fed a control diet (70 : 30 red clover silage (RC) : barley concentrate), a diet with sunflower seed (SS) substituted for barley, and diets with 15% or 30% wheat dried distillers' grain with solubles (DDGS-15 and DDGS-30) substituted for RC and SS. Perirenal fat (PRF) versus subcutaneous fat (SCF) had greater proportions of total saturated FA (SFA) and branched chain FA (BCFA), and lower proportions of total and major cis-monounsaturated FA (c-MUFA). Addition of SS to the diet did not change the proportions of total and major c-MUFA and n-6 polyunsaturated FA (PUFA), but led to decreases in the proportions of total and major SFA, BCFA and n-3 PUFA. Progressive substitutions with DDGS led to no further changes in the proportions of total and major SFA and n-3 PUFA, but decreased the proportions of BCFA and c9-16:1, and increased the proportions of c9-18:1 and n-6 PUFA. Feeding SS and DDGS-15 diets yielded the largest proportions of total and major t-18:1 (t11-and t13-/t14-18:1) isomers in PRF and conjugated lineolic acid (CLA) isomers (t7,c9- and t9,c11-18:2) in SCF, but responses were diminished when feeding the DDGS-30 diet. Subcutaneous fat versus PRF from steers fed SS and DGGS diets had larger proportions of non-conjugated 18:2 biohydrogenation products (i.e. atypical dienes) than the control diet. Overall, feeding SS and DDGS-15 diets raised the proportions of t11-18:1 in PRF and c9,t11-18:2 in SCF, which have potential human health benefits, but feeding DDGS-30 was less effective. <![CDATA[<b>Effects of niacin supplementation (40 weeks) and two dietary levels of concentrate on performance, blood and fatty acid profiles of dairy cattle</b>]]> The present study was conducted to investigate the effects of 24 g niacin (nicotinic acid (NA)) supplementation over 40 weeks with two forage-to-concentrate ratios (60% concentrate vs. 30% in the total diet) on performance variables of energy metabolism such as plasma concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose and nicotinamide (NAM), and the fatty acid profile in rumen fluid. In a 2 x 2 factorial design, 64 German Holstein cows were divided postpartum into four dietary groups: i) 60% concentrate supplemented with 24 g NA (Group 60 + NA); ii) 60% concentrate without NA (Group 60-); iii) 30% concentrate with 24 g NA (Group 30 + NA) and iv) 30% concentrate without NA (Group 30-). The experiment started on the day of calving and continued for 40 weeks. Niacin supplementation did not affect milk yield or composition. The plasma niacin content increased in the supplemented groups, especially Group 30 + NA. Niacin supplementation led to decreased plasma glucose concentrations. The interaction of concentrate x niacin enhanced the molar proportion of propionic acid in rumen fluid in Group 60 + NA. Total short-chain fatty acid (SCFA) concentrations were increased by level of concentrate, niacin supplementation and the interaction, concentrate x niacin. Plasma levels of NEFA and BHB remained unaffected. In sum, concentrate level, niacin supplementation and the interaction of concentrate x niacin increased plasma NAM concentration, whereas plasma glucose concentration was decreased by niacin supplementation. <![CDATA[<b>Milk fatty acid composition and conjugated linoleic acid content of Jersey and Fleckvieh x Jersey cows in a pasture-based feeding system</b>]]> A number of fatty acids (FAs), such as omega-3, omega-6 and conjugated linoleic acid (CLA), which are present in the milk from dairy cows are considered essential FAs and beneficial nutrients for humans. The aim of the study was to compare the milk FA content, particularly the CLA, omega-3 and omega-6 FA content of the milk fat of Jersey and Fleckvieh x Jersey (F x J) cows in a pasture-based feeding system. All cows were fed the same diet consisting of kikuyu-ryegrass pasture in a rotational grazing system supplemented with a standard commercial concentrate mixture at 7 kg per cow per day. Five milk samples were collected every five weeks from 10 days after calving, that is, days in milk (DIM) up to 175 DIM. In addition, two samples were collected every five weeks from 240 DIM to the end of the lactation period. Sampling was done at the evening and following morning's milking session and pooled for each cow. Samples were kept frozen at -20 °C until laboratory analysis by gas chromatography. Thirty six FAs were detected and concentration levels determined. Higher levels of total CLA (0.74 ± 0.02 vs. 0.63 ± 0.02 g FA/100 g fat), linoleic acid (1.51 ± 0.03 vs. 1.36 ± 0.04 g FA/100 g fat) and total omega-6 FAs (1.74 ± 0.04 vs. 1.54 ± 0.05 g FA/100 g fat) were recorded in the milk fat of F x J cows in comparison with Jersey cows, respectively. Increases in total CLA and the c9,t11 CLA isomers in the milk of Jersey and F x J cows followed the same trend, showing an increase from the beginning to the end of the lactation period. Similarly, the CLA content of the milk fat showed an increase with lactation stage for both breeds. <![CDATA[<b>Effects of prebiotics and probiotics on the performance and bacterial colonization of broiler chickens</b>]]> A study was undertaken to evaluate the effects of Neoxyval (antimicrobial growth promoter (AGP)), TechnoMos (prebiotic), GalliPro (probiotic) and a mixture of TechnoMos and GalliPro (symbiotic) on growth performance, carcass yield, histomorphology and intestinal bacterial counts in broilers (0 d to 42 d). Two hundred day-old Ross (308) broilers were allocated to five experimental treatments: T1 = control (CONT), T2 = T1 + Neoxyval, T3 = T1 + Gallipro, T4 = T1+ TechnoMos and T5 = T1+ Gallipro+ TechnoMos. The results revealed that birds that received T2, T4 and T3 gained more weight and converted feed more efficiently than those in T1 and T5. Longer ileal villi (492.9 μηι) were recorded in birds that received T4 compared with T1 (424.7 μπι) and T2 (439.9 μπι). Conversely, jejunal villi length and width were not influenced by treatment. T3 eliminated Clostridium perfringens from the ileum, but not from the caecum. Generally, birds that received T3 and T5 performed similar to the AGP group, T2. The results from this study indicated that the probiotic (T3) and prebiotic (T4) used in this trial could serve as alternatives to AGP (T2). Enhancement in the performance of broilers could be explained partially by improvement in intestinal morphology and microbial balance associated with modulation of intestinal microflora and inhibition of pathogens. <![CDATA[<b>Dietary effects of chitosan and buckwheat <i>(Fagopyrum esculentum) </i>on the performance and serum lipid profile of broiler chicks</b>]]> This study was conducted to evaluate the effects of different levels of buckwheat (Fagopyrum esculentum) alone or in combination with chitosan, in broiler diets, on the growth, feed intake and serum lipid profile of broilers. Starting as 10-day olds, 144 Cobb 500 broiler chicks were fed six manually prepared diets containing 0%, 10%, 20% or 30% buckwheat, or 10% buckwheat supplemented with 250 mg chitosan or 500 mg chitosan/kg. The trial lasted 32 days. Buckwheat alone or in combination with chitosan had no effects on the growth and feed intake of the broilers. Until 15 days lipid profiles in blood sera did not change in birds fed buckwheat alone or buckwheat in combination with chitosan. However, at day 30 the inclusion of 10% - 30% buckwheat alone and 10% buckwheat with 250 mg chitosan/kg or with 500 mg chitosan/kg showed a significant increase in serum HDL-cholesterol concentration and a decrease in total cholesterol, triglycerides and LDL-cholesterol concentrations in the serum compared with the control. This demonstrates for the first time that the feeding of higher levels of buckwheat (20% or more) alone or lower levels of buckwheat (10%) with trace amounts of chitosan influenced the lipid profiles of broilers positively. Because hazardous antibiotics are banned in poultry feed, including of buckwheat with trace amounts of chitosan in broiler diets might be a useful alternative to antibiotics in the poultry industry.