Browsing by Author "Hoffman, Louwrens C."
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- ItemCarcass yields and physiochemical meat quality of semi-extensive and intensively farmed impala (Aepyceros melampus)(MDPI, 2020) Needham, Tersia; Engels, Retha A.; Bures, Daniel; Kotrba, Radim; Van Rensburg, Berndt J.; Hoffman, Louwrens C.The effects of sex and production systems on carcass yield, meat quality and proximate composition of sub-adult impala were evaluated by culling 35 impala from intensive (12 males) and semi-extensive (12 males and 11 females) production systems within the same game farm. While no sexual dimorphism was found for carcass weights, male impala had a higher dressing percentage than females, indicating a higher meat production potential. Few differences were observed for yields between the male impala from the different production systems, but physical meat quality parameters indicated possible stress for those kept intensively. Minor differences existed in physiochemical parameters between various impala muscles for the two sexes and production systems, providing little motivation for these factors to be considered when processing sub-adult impala carcasses. Impala meat from both sexes, all muscles and all production systems produced meat with shear force values below 43 N, and thus may be considered as tender. Furthermore, the proximate composition of all impala meat in this study ranged from 74.7 to 77.0 g/100g moisture, 20.7 to 23.5 g/100g protein, 1.2 to 2.2 g/100g fat and 1.1 to 1.3 g/100g ash content. These values compare favorably to other game species, indicating that impala meat may serve as a lean protein source.
- ItemChemical composition of wild fallow deer (Dama Dama) meat from South Africa : a preliminary evaluation(MDPI, 2020) Cawthorn, Donna-Maree; Fitzhenry, Leon Brett; Kotrba, Radim; Bures, Daniel; Hoffman, Louwrens C.The effects of sex and production systems on carcass yield, meat quality and proximate composition of sub-adult impala were evaluated by culling 35 impala from intensive (12 males) and semi-extensive (12 males and 11 females) production systems within the same game farm. While no sexual dimorphism was found for carcass weights, male impala had a higher dressing percentage than females, indicating a higher meat production potential. Few differences were observed for yields between the male impala from the different production systems, but physical meat quality parameters indicated possible stress for those kept intensively. Minor differences existed in physiochemical parameters between various impala muscles for the two sexes and production systems, providing little motivation for these factors to be considered when processing sub-adult impala carcasses. Impala meat from both sexes, all muscles and all production systems produced meat with shear force values below 43 N, and thus may be considered as tender. Furthermore, the proximate composition of all impala meat in this study ranged from 74.7 to 77.0 g/100g moisture, 20.7 to 23.5 g/100g protein, 1.2 to 2.2 g/100g fat and 1.1 to 1.3 g/100g ash content. These values compare favorably to other game species, indicating that impala meat may serve as a lean protein source.
- ItemCombined effect of dietary protein, ractopamine, and immunocastration on boar taint compounds, and using testicle parameters as an indicator of success(MDPI, 2020-11-14) Needham, Tersia; Gous, Rob M.; Lambrechts, Helet; Pieterse, Elsje; Hoffman, Louwrens C.This study investigates the combined effect of immunocastration, dietary protein level (low, medium or high) and ractopamine hydrochloride supplementation (0 or 10 mg/kg) on the adipose concentrations of androstenone, skatole and indole in pigs, and explores whether body mass, carcass fatness or testicular parameters may be indicators of boar taint in these carcasses. Immunocastration was successful in decreasing testicle functioning, and adipose androstenone and skatole concentrations, in all individuals. Immunocastration decreased testicle weight and length, seminiferous tubule circumference and epithelium thickness. Testicle tissue from immunocastrates was also paler, and less red in color, in comparison to non-castrated controls. Dietary protein level and ractopamine hydrochloride supplementation had no influence on the adipose concentration of androstenone, skatole and indole. Testicle size and color were moderate to strong indicators of androstenone and skatole concentrations in the carcasses, and thus vaccination success. Immunocastration together with the adjustment of dietary protein and ractopamine hydrochloride supplementation, is successful in preventing boar taint while maintaining growth performance.
- ItemThe effect of barley and lysine supplementation of pasture-based diet on growth, carcass composition and physical quality attributes of meat from farmed Fallow Deer (Dama dama) the effect of barley and lysine supplementation of pasture-based diet on growth, carcass composition and physical quality attributes of meat from farmed Fallow Deer (Dama dama)(MDPI, 2019-01-24) Kudrnacova, Eva; Bures, Daniel; Barton, Ludek; Kotrba, Radim; Ceacero, Francisco; Hoffman, Louwrens C.; Kourimska, LenkaFallow deer (Dama dama) are important meat producing species providing venison and other products to an international market. The present study investigated the effects of different feed rations on the growth, carcass characteristics and physical attributes of the longissimus lumborum (LL) and semitendinosus (SET) muscles of 45 farm-raised male fallow deer. The animals were divided into three separate groups: 15 pasture-fed (P), 15 pasture-fed and supplemented with barley (B), and 15 pasture-fed and supplemented with barley and lysine (BL). The animals were slaughtered at an average age of 17 months at three time points: after 155, 169 and 183 days on feed. The addition of barley to the feed ration significantly increased weight gain and had positive effects on slaughter and carcass weights, dressing-out proportion, carcass composition, the weight of LL muscle, and increased the redness, yellowness and chroma values of LL muscle. The supplementation with lysine reduced the amounts of carcass and internal fats without compromising other economically important traits.
- ItemEffect of breed types and castration on carcass characteristics of Boer and large frame indigenous Veld goats of Southern Africa(MDPI, 2020) Van Wyk, Gertruida L.; Hoffman, Louwrens C.; Strydom, Phillip E.; Frylinck, LorindaWeaner male Boer Goats (BG; n = 36; 21 bucks and 15 wethers) and large frame Indigenous Veld Goats (IVG; n = 41; 21 bucks and 20 wethers) were raised on hay and natural grass ad libitum and the recommended amount of commercial pelleted diet to a live weight between 30 and 35 kg. Carcass quality characteristics (live weight, carcass weights, dressing %, chilling loss and eye muscle area) were measured. The right sides of the carcasses were divided into wholesale cuts and dissected into subcutaneous fat, meat and bone. Large frame Indigenous Veld Goat (IVG) wethers were slightly lighter than the IVG bucks with no significant difference observed between BG. Wethers compared to bucks had higher dressing %, subcutaneous fat % in all primal cuts, intramuscular fat %, kidney fat % and, overall, slightly less bone %. Some breed–wether interactions were noticed: IVG wethers were slightly lighter than the IVG bucks, but the IVG bucks tended to produce higher % meat compared to other test groups. Judged on the intramuscular fat % characteristics, it seems as if wethers should produce juicier and more flavorsome meat compared to bucks.
- ItemEffect of pork rind and soy protein on polony sensory attributes(OMICS International, 2015-01) Mapanda, Crispen; Hoffman, Louwrens C.; Mellett, Francois D.; Muller, NinaThis study determined whether commercially acceptable polony could be manufactured with varying quantities of chicken mechanically recovered meat (MRM), soy flour (S) and pork rind (R). The experimental design used was a two-factor, three-level factorial design, with various soy levels (0%, 4%, 8%) and pork rind (0%, 8%, 16%) resulting in nine treatments (R0S0, R0S4, R0S8, R8S0, R8S4, R8S8, R16S0, R16S4 and R16S8). Five treatment samples, R0S0, R0S4, R0S8, R8S0 and R8S4, which were indicated by the trained panel to have high market potential, were used to determine the degree of liking by consumers. Consumers liked the flavour and texture of treatments R0S0 and R0S4 which were strongly associated with pink colour, firmness and salty taste. Treatments R0S8, R8S0 and R8S4 were preferred less, mainly because they were associated with a perceptible soy flavour, pasty texture and white fat spots. The use of soy flour and pork rind is acceptable at <4% soy and <8% rind.
- ItemThe efficiency of probiotics administrated via different routes and doses in enhancing production performance, meat quality, gut morphology, and microbial profile of broiler chickens(MDPI, 2021-12-20) Soumeh, Elham A.; Del Rocio Coba Cedeno, Astrid; Niknafs, Shahram; Bromfield, Jacoba; Hoffman, Louwrens C.; Ravindran, VelmuruguTo study the efficiency of Bacillus spp. probiotics administered via different routes and doses, a 6-week grow-out trial was conducted using a total of 378 day-old mixed-sex ROSS308 broiler chickens in a completely randomized block design. Six experimental diets included probiotics added at two different inclusion rates into the feed (250 g/ton; PRO250, or 500 g/ton; PRO500), or in the drinking water (25 g/L; PRO-WS), or as a feed synbiotic (250 g probiotic + 250 g/ton prebiotic; SYN), compared to a negative (NC; without additives) and positive control (PC; with antibiotics) diets. The PRO-WS enhanced feed intake (p < 0.05) and tended to improve average daily gain and final body weight (p = 0.14). Broiler gut morphology in the duodenum including the villus height (p = 0.04), villus width (p = 0.05) and crypt depth (p = 0.02) were improved by PRO500. Firmicutes was the most abundant phylum, followed by Bacteroidetes. Streptococcaceae, Lachnoospiraceae, Peptostreptococcaceae, Ruminococcaceae, and Erysipe-lotrichaceae were the top five most abundant families. Antibiotic inclusion in PC reduced microbial beta-diversity and increased similarity compared to probiotic inclusion (p = 0.05). Probiotic inclusion reduced the relative abundance of Bacteroides fragilis, which is a commonly isolated pathogen and is considered as a marker for antimicrobial resistance. Overall, probiotic supplementation via feed or water may potentially improve the production performance of the broiler chickens, and water-soluble probiotics are potentially more effective. Probiotics, especially when added to water, suggest a promising feed additive to support gut microbial maturation and diversity, and may reduce resistant bacteria in broiler chickens. However, it is suggested that the best route for the administration of probiotics be further examined under commercial conditions to find the most effective and practical application method that yields the most consistent results.
- ItemGamebirds : a sustainable food source in Southern Africa(SpringerLink, 2013-02) Geldenhuys, Greta; Hoffman, Louwrens C.; Muller, NinaIn order to alleviate the current food security situation the world is faced with, it is essential to investigate meat sources which have the potential to be used in a sustainable manner. This review provides substantial arguments to prove the viability of sport hunted wildfowl as a food source in Southern Africa. However, before the use of wildfowl meat can be realised, there are certain challenges to overcome in order to ensure meat of the best possible quality reaches the consumer. Important aspects to consider regarding the eating quality of wildfowl meat are identified and include the physical activity of the different portions and muscle fibre types, diet, breeding, age and gender as well as the post mortem handling/ageing of the meat. The safety issues involved in producing gamebird meat i.e. shot contamination (microbial or lead), are also discussed. Other areas that warrant scientific research include investigating the intrinsic and extrinsic factors that may have an influence on the ultimate meat quality and exploring possible techniques of improving the eating quality of wildfowl meat. The insights these investigations will provide have the potential to increase the commercial viability, directly or indirectly, of African wildfowl meat and thus contribute to food security.
- ItemGuidelines for the harvesting & processing of wild game in Namibia 2016(Republic of Namibia, Ministry of Environment & Tourism, 2016) Van Schalkwyk, Diana L.; Hoffman, Louwrens C.The wildlife industry in Namibia has shown tremendous growth over the past decades and is currently the only extensive animal production system within the country that is expanding. Several factors are responsible for the dramatic increase in wildlife in range and numbers across Namibia with the most important being the devolution of rights over wildlife by the state to freehold landowners and communal conservancies. Tourism, live sales and trophy hunting have significantly contributed to the tremendous growth, however they cannot alone sustain further growth. Harvesting wildlife for the purpose of meat production is a viable option, since there is a demand for healthy and high quality meat proteins to feed the ever-increasing world population. It is also predicted that Namibia will experience climate changes in the near future which will further necessitate the optimal management of wildlife herds. The need to hygienically harvest game spearheaded the writing of this guideline booklet with the intention of it being used by Namibian game farmers and game harvesting teams. However, this booklet is a guideline and hence does not replace any regulatory food laws with regards to the harvesting and processing of game for commercial meat production.
- ItemA high incidence of species substitution and mislabelling detected in meat products sold in South Africa(Elsevier, 2013) Cawthorn, Donna-Maree; Steinman, Harris A.; Hoffman, Louwrens C.Due to their high market value, meat products are often targets for species substitution and adulteration. DNA-based methods are recognized as the most appropriate means to detect such fraudulent practices, however, these have not been extensively employed for the authentication of meat products available in South Africa. The aim of this study was to utilize a variety of molecular techniques to evaluate the extent of meat product mislabelling prevailing on the local market. A total of 139 processed meat products (minced meats, burger patties, deli meats, sausages and dried meats) were collected from retail outlets and butcheries in South Africa. The enzyme-linked immunosorbent assay (ELISA) was employed for the detection of undeclared plant proteins (soya and gluten) in the samples. A commercial DNA-based LCD array was used to screen the samples for the presence of 14 animal species, the results of which were confirmed by species-specific polymerase chain reaction (PCR) and in some cases also DNA sequencing. The results revealed that 95 of 139 (68%) samples contained species which were not declared on the product labelling, with the incidence being highest in sausages, burger patties and deli meats. Soya and gluten were identified as undeclared plant proteins in a large number of samples (>28%), while pork (37%) and chicken (23%) were the most commonly detected animal species. Unconventional species such as donkey, goat and water buffalo were also discovered in a number of products. Overall, this study confirmed that the mislabelling of processed meats is commonplace in South Africa and not only violates food labelling regulations, but also poses economic, religious, ethical and health impacts.
- ItemNon-destructive spectroscopic and imaging techniques for the detection of processed meat fraud(MDPI, 2021-02-18) Edwards, Kiah; Manley, Marena; Hoffman, Louwrens C.; Williams, Paul J.In recent years, meat authenticity awareness has increased and, in the fight to combat meat fraud, various analytical methods have been proposed and subsequently evaluated. Although these methods have shown the potential to detect low levels of adulteration with high reliability, they are destructive, time-consuming, labour-intensive, and expensive. Therefore, rendering them inappropriate for rapid analysis and early detection, particularly under the fast-paced production and processing environment of the meat industry. However, modern analytical methods could improve this process as the food industry moves towards methods that are non-destructive, non-invasive, simple, and on-line. This review investigates the feasibility of different non-destructive techniques used for processed meat authentication which could provide the meat industry with reliable and accurate real-time monitoring, in the near future.
- ItemNutrients composition in fit snacks made from ostrich, beef and chicken dried meat(MDPI, 2018) Zdanowska-Sasiadek, Zaneta; Marchewka, Joanna; Horbanczuk, Jarosław Olav; Wierzbicka, Agnieszka; Lipinska, Paulina; Jozwik, Artur; Atanasov, Atanas G.; Huminiecki, Lukasz; Sieron, Aleksander; Sieron, Karolina; Strzałkowska, Nina; Stelmasiak, Adrian; De Smet, Stefaan; Van Hecke, Thomas; Hoffman, Louwrens C.The aim of the study was to compare three types of meat snacks made from ostrich, beef, and chicken meat in relation to their nutrients content including fat, fatty acids, heme iron, and peptides, like anserine and carnosine, from which human health may potentially benefit. Dry meat samples were produced, from one type of muscle, obtained from ostrich (m. ambiens), beef (m. semimembranosus), and broiler chicken meat (m. pectoralis major). The composition of dried ostrich, beef, and chicken meat, with and without spices was compared. We show that meat snacks made from ostrich, beef, and chicken meat were characterized by high concentration of nutrients including proteins, minerals (heme iron especially in ostrich, than in beef), biologically active peptides (carnosine—in beef, anserine—in ostrich then in chicken meat). The, beneficial to human health, n-3 fatty acids levels differed significantly between species. Moreover, ostrich jerky contained four times less fat as compared to beef and half of that in chicken. In conclusion we can say that dried ostrich, beef, and chicken meat could be a good source of nutritional components.
- ItemAn overview of disease-free buffalo breeding projects with reference to the different systems used in South Africa(MDPI AG, 2012-11) Laubscher, Liesel L.; Hoffman, Louwrens C.This paper describes the successful national program initiated by the South African government to produce disease-free African buffalo so as to ensure the sustainability of this species due to threats from diseases. Buffalo are known carriers of foot-and-mouth disease, bovine tuberculosis, Corridor disease and brucellosis. A long-term program involving multiphase testing and a breeding scheme for buffalo is described where, after 10 years, a sustainable number of buffalo herds are now available that are free of these four diseases. A large portion of the success was attributable to the use of dairy cows as foster parents with the five-stage quarantine process proving highly effective in maintaining the “disease-free” status of both the calves and the foster cows. The projects proved the successfulness of breeding with African buffalo in a commercial system that was unique to African buffalo and maintained the “wildness” of the animals so that they could effectively be released back into the wild with minimal, if any, behavioral problems.
- ItemOxidative stability of blesbok, springbok and fallow deer droëwors with added rooibos extract(Academy of Science of South Africa, 2015) Jones, Maxine; Hoffman, Louwrens C.; Muller, MagdalenaThe addition of rooibos extract (RBE) (0%, 0.25%, 0.50%, 1.0% RBE) to improve the oxidative stability of blesbok, springbok and fallow deer droëwors (dried sausage) was studied. RBE treatments had no effects (p>0.05) on the lipid and protein oxidation of the dried product. With the addition of RBE 0.25%, lipid stability after drying showed the malonaldehydes decreased considerably. Haem-iron concentration increased after drying and differed (p<0.05) between RBE treatments within the dried stage within species. There were no differences (p>0.05) between the moisture, protein and fat contents between treatments within a specific processing stage. With the high polyunsaturated fatty acid content of the sausages, a high level of oxidation occurred. Even though RBE addition did not reduce oxidation significantly during the drying process, it could be a successful addition to the traditional South African meat product if it is shown to impart positive flavour attributes.
- ItemPhysical changes during post-mortem ageing of high-value impala (Aepyceros melampus) steaks(MDPI, 2020-06-29) Needham, Tersia; Engels, Retha A.; Hoffman, Louwrens C.Antelope meat production is rapidly growing, not only due to their adaptation to marginal land usage, but also because of its favorable nutritional properties and free-range production. However, limited information is available on the meat quality and processing potential of game meat for commercial consumption. The objective of this study was to determine the ageing period to achieve maximum tenderness of longissimus thoracis et lumborum (LTL) muscles of impala. The LTL muscles of 11 male and 11 female impala were harvested, and divided into eight portions. Each portion was randomly allocated to 1, 2, 4, 6, 8, 10, 12, or 14 days of wet-ageing (4 °C) in vacuum packaging. The meat pH, color, weep loss, cooking loss, and Warner–Bratzler shear force were measured throughout ageing. Initially the ageing profile differed depending on the sex of the animal from which the muscle was harvested; however, after 8 days of ageing, maximum tenderness was reached (13.5 ± 0.91 N) and no further sex differences were seen. Ageing improved the surface color of all meat until day 8, after which discoloration occurred. Therefore, it is recommended that impala LTL steaks should be wet-aged at 4 °C for eight days to achieve maximum tenderness and minimize sex variability.
- ItemProximate and fatty acid composition of cooked South African Cape snoek (Thyrsites atun)(Academy of Science of South Africa, 2017) Henning, Sune S.; Hoffman, Louwrens C.Cape snoek (Thyrsites atun) is an important source of protein for people in South Africa; however, nutritional information thereof is limited. The proximate and fatty acid compositions of raw and cooked (80 °C) snoek muscles were determined according to official AOAC methods. The mean moisture, ash, total lipids and protein for raw snoek were 72.8±1.86%, 1.3±0.09%, 4.0±1.16 and 21.5±1.35%, respectively. Cape snoek is very high in palmitic acid (24.65±1.43%), oleic acid (18.21±2.64%), eicosapentaenoic acid (EPA, 9.11±2.06%) and docosahexaenoic acid (DHA, 19.70±3.25%). With the exception of total lipids, cooking significantly reduced moisture (69.40±2.03%) and ash (1.12±0.12%), and increased protein (24.47±1.39%) content. It is concluded that Cape snoek is very high in protein and can be classified as a low-fat fish which is rich in EPA and DHA.
- ItemScale effects between body size and limb design in quadrupedal mammals(PLoS, 2013-11) Kilbourne, Brandon M.; Hoffman, Louwrens C.Recently the metabolic cost of swinging the limbs has been found to be much greater than previously thought, raising the possibility that limb rotational inertia influences the energetics of locomotion. Larger mammals have a lower mass-specific cost of transport than smaller mammals. The scaling of the mass-specific cost of transport is partly explained by decreasing stride frequency with increasing body size; however, it is unknown if limb rotational inertia also influences the mass-specific cost of transport. Limb length and inertial properties – limb mass, center of mass (COM) position, moment of inertia, radius of gyration, and natural frequency – were measured in 44 species of terrestrial mammals, spanning eight taxonomic orders. Limb length increases disproportionately with body mass via positive allometry (length / body mass0.40); the positive allometry of limb length may help explain the scaling of the metabolic cost of transport. When scaled against body mass, forelimb inertial properties, apart from mass, scale with positive allometry. Fore- and hindlimb mass scale according to geometric similarity (limb mass / body mass1.0), as do the remaining hindlimb inertial properties. The positive allometry of limb length is largely the result of absolute differences in limb inertial properties between mammalian subgroups. Though likely detrimental to locomotor costs in large mammals, scale effects in limb inertial properties appear to be concomitant with scale effects in sensorimotor control and locomotor ability in terrestrial mammals. Across mammals, the forelimb’s potential for angular acceleration scales according to geometric similarity, whereas the hindlimb’s potential for angular acceleration scales with positive allometry.