Distribution, utilization and management of the extra-limital common warthog (Phacochoerus africanus) in South Africa

[摘要] ENGLISH ABSTRACT: In South Africa, the recognition of wildlife as a natural resource has developed into a lucrative game farming industry where wildlife has value for tourism, recreational hunting and commercial hunting, including meat production and live sales. The modern game ranching industry is largely influenced by the demand of tourists and hunters for certain species and a great diversity of species, which has resulted in South Africa having the second highest rate of ungulate introductions globally. The common warthog (Phacochoerus africanus) was extra-limitally introduced to various game farms and reserves in the Eastern Cape, Northern Cape and the Free State provinces of South Africa for conservation and game farming purposes. Warthogs are not enclosed by the standard fencing used on agricultural lands and nature reserves, and have become free-roaming in the introduced habitats. The species currently inhabit both private and public lands on which major agricultural activities are practiced in South Africa and as a known agricultural pest, have become a managerial problem in traditional agricultural settings. The meat from hunted warthog carcasses is still relatively under-utilized by hunters and/or the commercial sector likely from a lack of information regarding the safety and preparation of the meat.The study found that introduced warthogs are simultaneously considered and managed as an agricultural pest and game animal by agricultural producers. This conflicting approach to management results in unethical and unsustainable control practices with undesirable outcomes for both farmers and warthogs. Since the majority of agricultural producers indicated that they would be more likely to utilize the meat if presented with information on its nutritional profile, the study proposed the production and utilization of warthog meat as fresh game meat or processed game meat products as a strategy to purposefully manage introduced warthog populations. There is a general concern that introduced warthogs could be responsible for introducing and transmitting diseases to animals and humans, and the consumption of warthog meat could cause diseases or parasitic infections in humans. The study found the first record of the tick Rhipicephalus gertrudae on warthogs in South Africa to date, while the low abundance of R. simus was attributed to the fact that the study area largely fell outside the ticks' preferred distribution range. Overall, the parasite species richness in the host population was low. These results may suggest that introduced warthogs can alter the distribution of parasites, and/or act as host to parasites not previously associated with warthogs. However, although warthogs are able to carry and transmit diseases to animals and humans, there is a lack of documented cases of this occurring in southern Africa outside of disease-controlled areas. In addition, no warthogs culled during this study showed obvious symptoms of diseases or carriers of parasites potentially harmful for human consumption, albeit this was not explicitly investigated in this study.The yields and meat quality characteristics of warthogs, and the use of warthog meat in processed products as determined in this study provides evidence that the species can be considered and utilized as a game animal for formal meat production. The overall carcass yields of warthogs were favourable and comparable to those of other wild ungulates, indicating production of warthog meat is economically feasible. Considering the effect of intrinsic factors such as sex and age, age appeared to have a more pronounced effect on the quality characteristics of warthog meat, while adult male warthogs had heavier body weights and higher yields compared to females. The study concluded that warthog meat should be marketed and labelled as whole muscle cuts considering the differences in quality characteristics among skeletal muscles. However, differences between sex, age and among muscles are considered negligible in terms of its nutrition and healthiness as the raw and cooked meat meat is high in protein (~ 20%) and low in fat (~ 2%) with a favourable polyunsaturated to saturated fatty acids ratio (PUFA:SFA) of < 0.45 and omega 6 to omega ratio 3 (ω6:ω3) ratio < 4, which is the recommended ratio for the human diet. However, the Longissimus lumborum (LL) muscle from warthogs culled on agricultural lands had a ω6:ω3 ratio > 4 compared to warthogs culled on a game reserve, while warthogs culled on the game reserve had higher levels of arachidonic acid. These differences were attributed to the differences in the regional and seasonal diet of warthogs.The sensory profile of warthog meat was dominated by pork aroma and flavour and tenderness, and it was proposed that total moisture content is an important factor influencing the sensory profile of warthog meat considering the overall low total fat. The meat was not described as being gamey, which raises the question of whether gamey attributes should be described as 'associated with game meat', and its aptness to distinguish among meat from different species. The study found the undesirable aroma and flavour described as 'sour/sweaty was not found only in adult males and was scored higher for juvenile warthogs of both sexes. The use of game meat in processed products could extend the value chain of game meat production, and the study found that warthog meat can be converted to healthy processed products without compromising the sensory attributes associated with the product, while providing further evidence that processes such as curing and smoking is able to reduce or 'mask' undesirable flavours. Neither sex nor age ultimately influenced the sensory profile of warthog back bacon produced from the Longissimus thoracis et lumborum muscle, which was overall high in total protein (~29%) and low in fat (< 2%) with a favourable fatty acid (FA) profile. The use of warthog meat in a ready-to-eat product known as cabanossi found that warthog and pork cabanossi had similar total protein (26.3% and 24.2%, respectively) contents, while the warthog cabanossi was lower in total fat content (6.9% and 13.7%, respectively), which did not affect consumer preference. Despite the encouraging results found in this study regarding the quality and properties of warthog meat, there are still many research questions regarding the distribution, impacts, utilization and management of warthog populations in South Africa. The study in its entirety provides baseline information pertaining to and influencing warthog yields and meat quality characteristics, and concludes that warthogs can be utilized as a game animal for meat production and utilization, with the benefit of producing an overall lean meat with desirable properties for processing.

[发布机构] Stellenbosch University