Scielo RSS <![CDATA[South African Journal of Animal Science]]> http://www.scielo.org.za/rss.php?pid=0375-158920200002&lang=es vol. 50 num. 2 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Variation in quality of newly hatched chicks from Japanese breeder quail fed guava extract</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200001&lng=es&nrm=iso&tlng=es The aim of this study was to evaluate the effects of guava extract as a dietary supplement for Japanese quail hens on incubation parameters, intestinal development, and the quality of newly hatched chicks. Six hundred and forty-eight eggs were collected from Japanese quail hens fed diets with 0.0, 3.0, 6.0, and 9.0 g/kg-1 of guava extract. The study consisted of four treatments, six replicates, and 27 eggs per replicate. The guava extract contained 2% ellagic acid. The eggs were incubated at 37.5 °C and 65% relative air humidity. The hatch window, hatchability, embryo development in unhatched eggs, quality of newly hatched quails, and intestinal histomorphometry of a duodenum segment were evaluated. Differences among the treatments in hatchability and the hatch window were not significant. The guava extract did not affect mortality rate, live pecking, dead pecking, and contaminated and inverted eggs. The number of infertile eggs was lower in the groups that received 3.0 and 9.0 g/kg of extract in their diets. Use of up to 3.0 g/kg of guava extract in the diet increased the weight of both eggs and newly hatched chicks. The quality score of newly hatched quail was similar across treatments. The inclusion of 3.0 g/kg of guava extract in the diet of Japanese quail breeder hens increased the hatchling weight of the chicks and improved the villus to crypt ratio of their duodenum. <![CDATA[<b>Impact of dried brewers' grains supplementation on performance, metabolism and meat quality of broiler chickens</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200002&lng=es&nrm=iso&tlng=es The objective was to evaluate increasing levels of dried brewers' grains (DBG) in feed for broiler chickens from 1 to 21 days old and their effect on performance, blood parameters, intestinal morphometry, carcass characteristics and meat quality. The design was completely randomized with six treatments, which consisted of various levels of DBG inclusion, namely 0 (no inclusion), 20, 40, 60, 80, and 100 g/kg with seven replications and 17 animals per experimental unit, totalling 714 male broilers. Performance parameters, blood biochemical profile, morphology of the intestinal epithelium (duodenum), and carcass yield and composition were evaluated. Feed intake was not changed by DBG inclusion levels. Nor were weight gain and feed conversion ratio. Serum cholesterol levels were not influenced, and there were no effects on triglyceride, uric acid and creatinine levels. Enzyme aspartate aminotransferase showed a quadratic effect, as did alanine aminotransferase, with higher values at 79.5 and 63.9 g/kg DBG inclusion, respectively. No changes in carcass yield and relative organ weight were observed. The composition of the carcass in ether extract showed a quadratic effect, as fat deposition rate, with lowest values at 62.8 and 62.4 g/kg of DBG inclusion levels, respectively. Crude protein levels in carcass reduced linearly, as did fat deposition rate. The parameters of intestinal morphology and meat quality were not changed. Dried brewers' grains can be included in broiler diet from 1 to 21 days at levels up to 100 g/kg without influencing the metabolic parameters and broiler performance. <![CDATA[<b>Fatty acid profile and oxidative stability of egg yolks from hens under different production systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200003&lng=es&nrm=iso&tlng=es This study was carried out to compare the egg quality, fatty acid (FA) profiles, and oxidative stability of yolks from hens maintained in cages and fed a conventional diet (CON), those fed a conventional diet with free access to outdoor grassy area (5 m²/hens) under free-range conditions (FR), and those fed an organic diet and free access to outdoor grassy area (10 m²/hens) under in organic system (ORG). Heavier eggs were produced by CON, while percentages of yolk and eggshell were greater in eggs of FR and ORG hens. The FR and ORG hens produced eggs that contained significantly more monounsaturated fatty acids (MUFAs) but less polyunsaturated fatty acids (PUFAs) than CON hens. Eggs from FR and ORG hens had a lower concentration of PUFA n-6 because of less C18:2 n-6 (linoleic acid) and a higher percentage of PUFA n-3 (eicosapentaenoic acid). Consequently, the ratio of PUFA n-6 to n-3 for eggs from FR and ORG hens was healthier for consumers compared with CON. However, eggs from the ORG hens had a similar FA profile to those from the FR hens. No significant differences were noted in hypocholesterolaemic (HI), atherogenic (AI) and thrombogenic indexes. Antioxidant concentration was greatest in eggs from ORG hens (retinol-14.32 μ/g and a-tocopherol-98.7 μ/g/yolk). Thus, the oxidative stability of eggs measured after storage at 4°Cfor 15 or 30 days was improved. The best eggs in terms of nutritional value were from the ORG system in which hens lived in their natural environment. <![CDATA[<b>Manipulating the onset of lambing season in communal ewes through hormonal vintervention</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200004&lng=es&nrm=iso&tlng=es The study was conducted to evaluate the effectiveness of using long-acting medroxyprogesterone acetate (MPA) to delay the lambing season in communal wool sheep ewes. The study was conducted in three phases. In phase 1, a random assessment was made to determine whether the hormone had any effect on delaying the onset of the lambing season. In the second phase, the administration of the hormone at different times during the perceived mating season was assessed. In the third phase, it was investigated whether the use of the hormone had residual effects in the subsequent lambing season after the treatment was discontinued. From the results it is evident that the administration of 150 mg MPA before conception could delay lambing between two and three months. November seems to be the optimum month for hormone administration. However, administration of the hormone did not guarantee effective prevention of conception in all treated ewes and discontinuation of treatment resulted in ewes reverting to pre-treatment lambing patterns. In conclusion, long-acting MPA can be used selectively as an effective method to delay the lambing season in communal ewes and to manipulate it towards more favourable environmental conditions for ewes and lambs. There can be a seasonal effect on time of conception in communal ewes and this should be considered when timing a hormonal treatment protocol. <![CDATA[<b>Selenium and nano-selenium ameliorations in two breeds of broiler chickens exposed to heat stress</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200005&lng=es&nrm=iso&tlng=es The objective of this study was to compare the effects of synthesized nano-selenium (NS) and commercial inorganic selenium (Se) on immunity, behaviour, and performance of Arbor (AB) and Ross (RB) broilers that were exposed to heat stress of 40 °C for 6 - 8 hours daily over 38 days. Two hundred and ten one-day-old broilers of two breeds were supplemented with 0.5 mL/L of NS or Se in their drinking water. Two hundred sera, 200 intestinal swabs, and 1000 internal organ and tissue samples were collected. Weight gain, performance index, behavioral indices, total antioxidant capacity, malondialdehyde, superoxide dismutase, immunoglobulin G, immunoglobulin M, serum total protein, albumin, alanine aminotransferase, aspartate aminotransferase, and serum creatinine concentrations increased (P <0.01) in RB compared with AB when supplemented with NS. Meanwhile, NS supplementation decreased (P <0.01) water intake and the logarithmic bacterial counts of the intestine and breast in RB and AB, respectively. Histopathology revealed mild leukocytic infiltration and mild vacuolar degeneration in hepatocytes, and focal leukocytic infiltration, mild congestion, and cytoplasmic vacuolation in the myocardium of RB. Photomicrographs showed a mild lymphoid depletion in the spleen, while histopathology of the bursa of Fabricius revealed a normal follicular epithelium and normal lymphoid follicles with mild inter-follicular fibrosis in RB that were supplied with NS as opposed to AB, which expressed more severe pathological affections from heat stress. Thus, NS was more effective than Se in allowing broilers to respond to heat stress. <![CDATA[<b>Ingestive behaviour and performance of feedlot lambs fed saccharine sorghum and corn silages</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200006&lng=es&nrm=iso&tlng=es This study evaluated the ingestive behaviour and performance of feedlot lambs fed saccharine sorghum and corn silages. Ten animals were randomly selected from a group of 32 uncastrated male Suffolk lambs. The four treatments consisted of diets with 50% of silage made from forage sorghum (BD 1615), two varieties of saccharine sorghum (BRS 506 and BRS 511), and corn (BRS 2223). Ingestive behaviour was observed by a scan sampling method using seven strategically positioned video cameras so as not to interfere with the usual animal behaviour. The animals were observed for three 48-hour periods at 15-day intervals, with a total of 144 hours of observation. Video recordings were then examined to identify the time spent in ruminating, eating, drinking water and idling. Times spent feeding or drinking water were not significantly affected by the treatments. Animals fed forage sorghum silage had higher neutral detergent fibre (NDF) intake (0.41 kg of NDF), thus spent more time ruminating (342 min/day). Rumination time was similar for the BD 1615 and BRS 506 silages and was 85 min/day greater than for the BRS 511 and BRS 2223 silages, which were similar. Average daily gain was greater for BRS 2223 (275 g/day) than for BRS 506 and BRS 511 silages, which were similar (196 g/day). Ingestive behaviour for BRS 511 was similar to that observed for BRS 2223. Ingestive behaviour for BRS 506 was similar to that observed for BD 1615. Average daily gain was related to intake and ruminating efficiency. <![CDATA[<b>Performance, intestinal histomorphology and bone composition of broiler chickens fed diets supplemented with genistein</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200007&lng=es&nrm=iso&tlng=es The effect of dietary genistein on performance, intestinal morphology, caecal Lactobacillus spp. count, and tibia composition in broiler chickens after 21 and 37 days of feeding was investigated. A total of 360 Cobb 500 broiler chickens (21 days old) were randomly allocated to five treatments with six replicates of 12 birds each. They were fed a basal diet (C) or a basal diet supplemented with 200 (T1), 400 (T2), 600 (T3) and 800 (T4) mg genistein/kg of feed. Genistein supplementation did not affect feed intake, but improved bodyweight, weight gain and feed conversion ratio (FCR) after 21 days, while 600 mg/kg led to a significant increase in FCR after 37 days of feeding. Plasma triglyceride level decreased with dietary genistein after 21 days, while increases were found in T3 and T4 groups after prolonged supplementation. Significantly improved duodenal and jejunal villus length and width, crypt depth and villus/crypt ratio were observed after the first and the second finishing periods, respectively, while adverse effects were found in the ileum for both periods. At 42 days old, greater spleen and heart weights were measured in broilers fed diets with 800 mg/kg than in other broiler groups. The shorter genistein supplementation period (21 days) of 200 and 400 mg/kg had a positive effect on tibia wet weight, ash and calcium (Ca) content, while 37 days of the higher genistein doses administered to the T2, T3 and T4 birds significantly increased caecal lactic acid bacteria (LAB) counts. Thus, recommended doses should not exceed 400 mg/kg. <![CDATA[<b>Supplemental linseed oil and antioxidants affect fatty acid composition, oxidation and colour stability of frozen pork</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200008&lng=es&nrm=iso&tlng=es The aim of this study was to evaluate the influence of dietary linseed oil and antioxidants on the quality of fresh and frozen pork neck stored at -20 °C for six and 12 months. Polish Landrace x Duroc pigs were fed a standard diet (C), a diet supplemented with 3% linseed oil (L1), or a diet with 3% of linseed oil, 1 mg organic selenium (SE)/kg, and 100 mg vitamin E/kg (L2). Chemical components, fatty acid profile and vitamin E content were determined in the fresh meat. Colour, pH and change in the profiles of certain volatile compounds (alcohols, aldehydes, ketones, and esters) were monitored during frozen storage. An electronic nose technique, which was based on ultra-fast gas chromatography, was used to evaluate changes in the profiles of the volatile compounds. After six months of frozen storage, oxidative processes were slower and similar in groups L1 and L2, but less so in meat from C. In pork that was stored for six months, lipid oxidation was not affected by supplementation only with linseed oil (L1). After 12 months of frozen storage, a reduced rate of increase in alcohols, aldehydes and ketones was observed in pork from L2 relative to L1 and C. Lipid oxidation processes in long-stored frozen pork neck were inhibited by the addition of antioxidants to L2. However, a total colour change (ΔE*) of the pork from L1 and L2 was found during storage, which might influence consumers' decisions to purchase the product. <![CDATA[<b>Immunoglobulin G response and performance in Holstein calves supplemented with garlic powder and probiotics</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200009&lng=es&nrm=iso&tlng=es The study evaluated the effects of garlic, probiotics, and in combination on levels of immunoglobulin G (IgG) and growth performance in new-born Holstein calves. Thirty-two Holstein calves were randomly allocated to treatments at four days old and were maintained on them until they were 42 days old. The treatments consisted of control (C), garlic powder at 5 g/calf/day (GA), probiotics at 4 g/calf/day (PB), and the combination of garlic and probiotics (GP). Bodyweight, body length and heart girth measurements were taken to determine growth and blood was drawn to determine glucose and IgG. Faecal score and body temperature were recorded daily. Calves in GA and GP had higher IgG levels than calves in C and PB (28.0 g/L and 27.5 g/L versus 23.5 g/L and 25.5 g/L, respectively). Calves in GP and PB groups had lower faecal scores than C and GA (2.1 and 2.1 versus 2.3 and 2.2, respectively). Supplementation of GA, PB, and in combination did not affect feed intake and growth performance negatively, but improved serum IgG levels. Higher serum IgG in GP may indicate an improved intake and utilisation of nutrients that are responsible for immunity modulation and regulation. Probiotics and their combinations with garlic have the potential to reduce the incidence of diarrhoea when fed to young calves. <![CDATA[<b>Behaviour and stress in three breeds of laying hens kept in the same environment</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892020000200010&lng=es&nrm=iso&tlng=es The aim of the study was to determine whether birds of different breeds, with different preferences for environmental elements and kept in identical conditions, would exhibit different behaviour and stress levels. The research material consisted of 50 laying hens of the Green-legged partridge (Zk), Polbar (Pb), and Leghorn (Lg) breeds. The birds were provided with identical environmental conditions. They were kept on litter in separate boxes, with 25 individuals of one breed per box, in the same building. An open field test was used in determining the behaviour of the birds. Levels of cortisol in serum and corticosterone in feathers were evaluated, and haematological and biochemical analyses of blood were performed. Leghorns proved to be a highly excitable and active breed whose needs cannot be fully satisfied in the standard conditions of large farms. Based on a differential leukocyte count, their hyperactivity was associated with increased stress. The Green-legged partridge exhibited the lowest stress levels. Birds kept in the same environmental conditions were found to differ significantly in the level of stress, probably because of differences in their behavioural needs and the possibilities of satisfying them. To reduce stress levels and improve the welfare of hens, it is necessary to verify their preferences first. Stress indicators are elevated in highly excitable birds, and the conditions on large farms are not conducive to meeting their behavioural needs.