Scielo RSS <![CDATA[South African Journal of Animal Science]]> http://www.scielo.org.za/rss.php?pid=0375-158920210002&lang=en vol. 51 num. 2 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Effects of stocking density on growth and skin quality of grower Nile crocodiles<i> (Crocodylus niloticus)</i></b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200001&lng=en&nrm=iso&tlng=en Intensive Nile crocodile (Crocodylus niloticus) farming operates with considerable variation in housing and stocking density. In this study, current commercial stocking densities for crocodilians were investigated using 261 grower-phase crocodiles (15 months old, average total body length 94.5 cm, and average weight 2.7 kg). Low (2.60 m² per crocodile), medium (1.24 m² per crocodile), and high (0.41 m² per crocodile) stocking densities were tested. Growth, morphometric measures, Fulton's condition scores and skin qualities were assessed over a six-month (May - November 2017) period. High stocking density had no adverse effects on the growth of grower Nile crocodiles. Crocodiles stocked at medium and high densities outperformed those that were stocked at low density in Fulton's body condition scores, change in body condition from the start to the end of the trial, and feed conversion efficiencies. However, the high and, to a lesser extent, the medium stocking densities resulted in lower skin quality scores compared with those in the low-density treatment because of teeth marks from more aggressive behaviour. The results indicated that the medium pen density treatment is closer to the ideal than either the high or low stocking density groups. Stocking densities that provide 0.41 m² per crocodile or less should be avoided because of lower skin quality scores, which weigh more heavily than growth and feed efficiency responses in the financial viability of commercial crocodile farming in typical South African production systems. <![CDATA[<b>Correlation between live weight and body measurements in certain dog breeds</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200002&lng=en&nrm=iso&tlng=en The purpose of this study was to determine the correlation between live weight and body measurements in Zagar, Zerdava, and Çatalburun dogs. Animal materials were obtained from various regions of Turkey. A total of 304 dogs from three breeds were used: Zagar (45 females, 59 males), Zerdava (50 females, 50 males), and Çatalburun (62 females, 38 males). Live weights and certain body measurements were determined. A linear regression model was created using the parameters obtained in this study. The bodyweights calculated with the body measurements were found to be at a high or acceptable level in the Zagar, Zerdava, and Çatalburun genotypes (R² = 0.902, 0.467, and 0.697, respectively). <![CDATA[<b>Influence of phytate and phytase on performance, bone, and blood parameters of broilers at 42 days old</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200003&lng=en&nrm=iso&tlng=en The objective was to evaluate the effect of diets containing various levels of phytate and phytase on broilers from 1 to 42 days old. The treatments consisted of a combination of diets containing high (HP), medium (MP) and low (LP) phytate with positive control diet (PC) and a negative control diet (NC) that was similar to the PC in energy and protein but with less calcium and phosphorus. Three additional diets, based on the NC were supplemented with 500, 1000, or 1500 FTU kg-1 of phytase. Broilers that received the NC diet exhibited the lowest weight gain (WG), whereas those supplemented with 1000 FTU kg-1 obtained 2.84% higher WG compared with PC. Broilers that received NC had the lowest breaking strength and dry matter. Birds fed HP diets that received NC and NC + 500 FTU kg-1 had a higher concentration of serum Ca and P than birds fed LP diets. Broilers fed the NC and NC + 500 and 1000 FTU kg-1 had lower tibia Ca levels compared with birds fed the PC. Broilers fed HP diets had higher tibia Ca content than MP. Phytase supplementation had a positive response in diets with reduced Ca and P. Based on regression analysis the optimum inclusion of phytase to improve broiler performance parameters was calculated as 952 FTU kg-1. <![CDATA[<b>Effects of orégano essential oil and capsicum extract on fattening, serum constituents, and rumen fermentation of lambs</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200004&lng=en&nrm=iso&tlng=en This study investigated dietary supplementation of weaned lambs with Origanum vulgare essential oil and Capsicum oleoresin (chilli pepper) extract. Thirty-six eight-week-old male and female Menemen lambs were used in this study. Three dietary treatment groups consisted of T1, an unsupplemented control group; T2, a group supplemented with 300 mg/kg oregano essential oil, and T3, a group supplemented with 300 mg/kg Capsicum oleoresin. Feed and fresh water were available to the lambs ad libitum during the 56-day experiment. No significant effects of treatment were detected on growth rate, feed intake and feed conversion. In addition, serum urea, creatine, total protein, albumin, amylase, aspartate amino transferase (AST), alanine amino transferase (ALT), and gamma glutamyl transferase (GGT) levels did not differ among treatments on day 56 of the study. When oregano oil and capsicum extract were added to the feed, total volatile fatty acids (TVFA), acetate (AA), propionate (PA), butyrate (BA), isobutyrate (IBA), valerate (VA), and AA to PA ratio in the rumen were decreased significantly in comparison with the control group at two hours after feeding, with the effect of T2 being greater than that of T3. Female lambs had lower levels of TVFA than male lambs. Thus, although neither additive affected fattening performance and serum constituents of the lambs, both altered the rumen fatty acid profile. <![CDATA[<b>Effects of different feeding methods on neuropeptide nesfatin-1 and irisin in turkeys</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200005&lng=en&nrm=iso&tlng=en In this study, the effects of different methods of feeding turkeys on the neuropeptide nesfatin-1 and the hormone irisin were evaluated. A total of 90 turkeys were distributed to three treatment groups, namely T1: conventional system, T2: 50% feed and pasture, and T3: pasture. There were 30 birds in each group with three random replications. The birds were fed for 18 weeks. At the end of the study, blood was collected from 10 birds of each group. Plasma nesfatin-1 and irisin levels were measured with an enzyme-linked immunoassay. The nesfatin-1 levels of male turkeys in T1, T2, and T3 were 0.76 ± 0.1 ng/m, 0.41 ± 0.1 ng/ml, and 1.24 ± 0.2 ng/ml, respectively. Nesfatin-1 levels in the female turkeys in T1, T2 and T3 were 0.53 ± 0.07 ng/ml, 1.18 ± 0.3 ng/ml, 1.32 ± 0.1 ng/ml, respectively. The irisin levels in the male turkeys in T1, T2, and T3 were 575.93 ± 42.5 pg/ml, 188.39 ± 1.8 pg/ml, and 607.54 ± 24.1 pg/ml, respectively. Irisin levels of the female turkeys in T1, T2 and T3 were 603.20 ± 42.2 pg/ml, 241.42 ± 18.4 pg/ml, and 399.29 ± 21.5 pg/ml, respectively. Because nesfatin-1 is involved in regulating food intake, food intake by turkeys might differ, depending on the management system. Different management systems might also alter irisin secreation because it can be induced by exercise. <![CDATA[<b>Factors affecting In vitro methane production from cecum contents of White Roman geese</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200006&lng=en&nrm=iso&tlng=en The goal of this research was to gain understanding of in vitro methane (CH4) production from the cecal contents of White Roman geese under various incubation conditions. Five experiments were conducted to ascertain the effects of i) incubation time, ii) pH, iii) the addition of formic acid to the culture media, iv) temperature, and v) the addition of salt to the nutritive liquid. Methane production increased significantly with the supplementation of formic acid in the culture fluid (Experiment III). Additionally, CH4 production Experiment V was higher than that without saline. In contrast, low CH4 production occurred under acidic conditions (pH< 5.4) and at temperatures higher or lower than typical bird body temperature (43 °C) without formic acid and saline solution in the culture media. Since bird body temperature cannot be controlled easily, approaches such as maintaining cecum fluid at low pH and preventing the formation of formic acid by adjusting the recipes of feeds could be considered for controlling in vivo CH4 production from the intestinal tract digesta of geese. <![CDATA[<b>Ovarian dynamics, hormone profiles, and characterization of ovarian and uterine blood flow in cycling Sahiwal cows</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200007&lng=en&nrm=iso&tlng=en The objectives were to investigate the ovarian dynamics and hormonal profiles during the oestrus cycle, and to characterize the ovarian and uterine blood flow (OBF versus UBF) indices on the extent of vascular perfusion towards the dominant follicle (DF) or corpus luteum (CL) during the peri-ovulatory follicular wave in Sahiwal cows. In experiment 1, cyclic cows (n = 21) were selected at their spontaneous oestrus (day 0) and subjected to B-mode ultrasonography throughout the oestrus cycle. In experiment 2, cyclic cows (n = 9) were randomly selected at day 0, and categorized according to the intra-ovarian patterns as ovaries with DF (n = 3), CL (n = 3) or both (DF+CL; n = 3) to characterize the OBF and UBF indices using Doppler ultrasonography. The length of the oestrus cycle (days), number of follicular waves (n) and size (mm) of DF and CL were 20.1 ± 0.9, 2.1 ± 0.2, 14.7 ± 0.7 and 15.9 ± 2.5, respectively. The concentrations (ng/mL) of plasma progesterone increased linearly, and a peak was attained at day 12.2 ± 1.0. However, it reduced linearly with the onset of luteolysis at day 16.4 ± 0.3 of the oestrus cycle. The plasma progesterone (P4) concentrations and the diameter of CL correlated throughout the oestrus cycle. The mean OBF and UBF indices did not differ between intraovarian patterns. Taken together, this information on reproductive physiological parameters could be used to develop synchronization protocols to improve reproductive management in Sahiwal cows. <![CDATA[<b>Effects of ventilation programme and eggshell thickness on hatchability rate and hatching time of broiler eggs</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200008&lng=en&nrm=iso&tlng=en The aim of the research was to determine whether enrichment of the atmosphere in an incubator with carbon dioxide (CO2) and oxygen (O2) and eggshell thickness (EST) affected embryonic death (ED), hatchability of fertile eggs (HFE) and hatching time (HT). A total of 320 Ross 308 eggs were used and the experiment was repeated twice. Eggshell thickness was classified as thin (<31 μηι), medium (31 - 32 μηι) and thick (&gt;32 μπι). The incubators were operated with their internal atmosphere enriched with CO2 (1.57% CO2; 20.23% O2) or O2 (0.50% CO2; 22.44% O2). Embryonic death, HFE and HT data were monitored at three periods, namely early (<486 hours), middle (486 - 492 hours), and late (492 - 510 hours). Early ED, late ED and hatchability of fertile eggs were not affected by EST or by the incubator's internal atmosphere (P &gt;0.05). Thus, O2 supplementation to the incubator was deemed unnecessary at 822 m altitude. There was a highly significant interaction between EST and HT. Eggs with shells 31 to 32 μπι thick hatched at an appreciably greater rate between 486 and 492 hours of incubation (17%) than eggs with thicker (0.6%) or thinner (0.4%) shells in both the CO2 and O2 enriched atmospheres. The hatching rate was significantly higher in the eggs with an intermediate EST than in thick-shelled eggs. A greater proportion of eggs hatched at the late HT as opposed to earlier, regardless of EST. <![CDATA[<b>Fatty acid profile and in vitro rumen fermentation characteristics of maize silage augmented with canola silage</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200009&lng=en&nrm=iso&tlng=en The objective was to investigate the effect of replacing maize silage (MS) with canola silage (CS) on the chemical composition and fatty acid (FA) profile of total mixed rations (TMR) containing these silages, and on in vitro rumen fermentation and methane production from them. The canola (Brassica napus var. Monty) was cultivated on a small-scale agricultural farm and harvested at 148 days after sowing. Maize silage in a TMR was replaced with 0%, 15%, 25%, and 35% CS to make the rations CS0, CS15, CS25, and CS35, respectively. Proximate analyses of the rations were evaluated in a completely randomized design. The results showed that linolenic acid increased linearly with the level of CS, primarily at the expense of linoleic acid. In vitro dry matter digestibility (IVDMD) was similar among treatments. However, in vitro neutral detergent fibre digestibility (ivNDF) decreased linearly (P <0.05) when the CS proportion increased in the TMR. The lowest ammonia nitrogen content (P <0.05) was observed in CS35. The soluble fraction (A) increased (P <0.05) when the CS increased in the TMR from 0% to 35%. In vitro methane (CH4) production was lowest with CS25 and CS35, decreasing 34% and 23.9%, respectively, compared with CS0. Linolenic acid had a negative correlation with IVNDF (r = -0.94; P <0.05). The IVDMD and methane production were positively correlated (r = 0.60) (P <0.05). In conclusion, 25% and 35% augmentation of MS with CS in a TMR was an important source of linolenic acid (C18:3) and decreased in vitro methane production. <![CDATA[<b>Effect of mentha on performance, haematological and biochemical parameters in laying hens</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200010&lng=en&nrm=iso&tlng=en Effects of Mentha piperita (peppermint) extract and juice on performance and immune parameters were evaluated in laying hens. A total of 252 Babcock laying hens were allocated to seven treatments with four replications of nine hens. The control hens were fed a basal diet without supplementation. Other hens were given diets supplemented with mentha extract (ME) at 50 (50ME), 100 (100ME), and 200 (200ME) mg/kg of feed or with 50 mentha juice (50MJ), 100 (100MJ) and 200 (200MJ) mg/L that was provided in the drinking water. No significant differences were detected among treatments in bodyweight, feed intake, egg mass, egg production, eggshell breaking strength, Haugh unit, and haematological and serological parameters. The ratio of gram feed to gram egg mass (feed conversion) was significantly better in the birds that received 100ME and 200ME compared with the control hens. The yolk colour index was higher in mid trial analysis (28th day). Thus, although the ME supplementation had a positive effect on feed conversion ratio and egg yolk colour at dosage rates up to 200 mg/kg, further research is needed to establish the efficacy of this herbal product and to determine the most appropriate amount to include in diets for laying hens. <![CDATA[<b>Carcass characteristics and meat quality of sheep fed buffelgrass silage to replace corn silage</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200011&lng=en&nrm=iso&tlng=en The aim of the study was to evaluate the carcass characteristics, proximate composition, and sensorial attributes of meat from sheep fed diets in which buffelgrass silage replaced corn silage. Thirty-two intact male crossbred Santa Inês sheep with an average live weight of 20.09 ± 2.0 kg were housed in individual stalls and allotted at random to four treatments in which corn silage was replaced by buffelgrass silage at the levels of 0 (control), 33.3%, 66.6%, and 100%. After an adaption period of 10 days, the sheep were fed for an additional 61 days. Feed was offered ad libitum and corn silage comprised 60% of the diet for the control group. Carcass characteristics, non-carcass components and meat quality were evaluated. Hot carcass yield, cold carcass yield, true carcass yield, trimmings, fat weight, and mesenteric and omental fat weight were highest for the control group (P <0.05). Loin eye area had a quadratic response (P =0.02), with the largest areas being observed in animals fed the diet containing 66.6% buffelgrass silage. Liver weight (P <0.01), luminosity of the meat (P <0.05), and cooking loss (P <0.05) likewise had nonlinear responses to the concentration of buffelgrass silage in the diet. The treatments did not have significant negative influence on the nutritional and organoleptic characteristics of the meat. <![CDATA[<b>Traceability to ensure food safety and consumer protection as typified by case studies of three meat processing plants</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200012&lng=en&nrm=iso&tlng=en Ensuring food safety is a legal obligation of the manufacturer or of the entity that places the product on sale. Traceability is one of the tools that are used to ensure food safety. It allows the withdrawal of a dangerous or non-compliant product from the market and determines the source of a threat. The aim of the study was to compare the functioning and effectiveness of traceability systems in selected approved meat industry plants. The system functioning in a large meat processing plant, in which the circulation of documents was implemented in a computer system, was compared with two smaller ones, in which paper documentation was carried out, but supported by a computer system. In these plants, the traceability system was based on internal procedures. Properly developed traceability procedures and simulations support and enable response in a crisis. Computer systems streamline and facilitate the traceability process. However, the comparative analysis showed that the use of paper records allowed for efficient identification of the source of the threat. The possibility of performing product traceability was confirmed in these plants. Internal markings and codes and documentation flow, staff training, and awareness proved helpful. <![CDATA[<b>Effects of production system and feeding regimen on carcass and meat quality traits of Naked Neck chicken</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200013&lng=en&nrm=iso&tlng=en To evaluate the effect of a production system and feeding regimen on meat quality attributes of Naked Neck chickens, a total of 150 cockerels at 18 weeks old (1625 ± 70 g) were collected from 10 treatment groups with five replicates of three birds. The factorial arrangement of treatments consisted of two production systems (intensive and free-range) and five nutritional regimens, namely 100% commercial feed; 75% commercial feed plus 25% kitchen waste; 50% commercial feed plus 50% kitchen waste; 25% commercial feed plus 75% kitchen waste; and 100% kitchen waste. Carcass traits, meat quality, and meat organoleptic were found to differ significantly among production systems, feeding regimens, and their interaction. Higher liver weight was observed in birds reared under an intensive system. Higher gizzard weight was noted in birds fed with 100% kitchen waste, whereas lower gizzard weight was observed in birds fed the commercial diet. The meat from cockerels fed with 75% kitchen waste was most yellow, whereas the meat from the birds fed with 100% kitchen waste was least yellow. At two hours after slaughter, pH of the meat was highest in birds fed 50% kitchen waste and lowest in birds fed 100% kitchen waste. The interaction of production system and feeding regimen was significant for overall acceptability score. In conclusion, Naked Neck chickens performed equally well under intensive and free-range systems, irrespective of the level of kitchen waste that they were fed. <![CDATA[<b>Inclusion of rapeseed and pumpkin seed cakes in diets for Murciano-Granadina goats alters the fatty acid profile of milk</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892021000200014&lng=en&nrm=iso&tlng=en The objective of this research was to assess the effects of including oil-rich feedstuffs in diets for lactating goats on the fatty acid (FA) profile of their milk. Thirty-six Murciano-Granadina goats were randomly assigned to three treatment groups, namely a control diet (CTRL), a diet based on whole rapeseed (RS), and a diet based on pumpkin seed cake (PSC). The diets were composed of 1 kg hay (70 % Italian ryegrass, 30% alfalfa) and 1.24 kg concentrate, and were formulated to be isoenergetic and isonitrogenous. Milk yield and its contents of protein, fat and lactose did not differ significantly among the groups. However, including oil-rich feeds in the diet altered the fatty acid profile of the milk significantly, decreasing its saturated fatty acid (SFA) content and increasing its content of unsaturated fatty acids (UFAs). Effects on polyunsaturated fatty acids (PUFAs), conjugated linoleic acid (CLA), and the n-6 to n-3 ratio depended on the source of dietary lipids. The PSC augmented diet increased the relative amount of PUFAs and fatty acid methyl esters (FAME) in milk (+25 %) significantly In comparison with CTRL, whereas the RS diet produced a limited and statistically insignificant increase (+7.5%). The concentration of CLA was higher in milk from does fed the PSC diet, whereas the n-6 to n-3 ratio was lower in milk from does fed RS. These preliminary results form the basis for developing premium dairy products that are enriched in fatty acids that are more favourable for human health.