Impact of season on the fatty acid profiles of male and female blesbok (Damaliscus pygargus phillipsi) muscles

Meat Science 98 (2014) 599–606

Contents lists available at ScienceDirect

Meat Science journal homepage: www.elsevier.com/locate/meatsci

Impact of season on the fatty acid profiles of male and female blesbok (Damaliscus pygargus phillipsi) muscles J. Neethling a,b, T.J. Britz a, L.C. Hoffman b,⁎ a b

Department of Food Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa Department of Animal Sciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa

a r t i c l e

i n f o

Article history: Received 19 June 2013 Received in revised form 11 June 2014 Accepted 20 June 2014 Available online 28 June 2014 Keywords: Blesbok Fatty acid Game Muscle Season Venison

a b s t r a c t This study quantified the impact of season on fatty acid profiles of male and female blesbok muscles (longissimus thoracis et lumborum, biceps femoris, semimembranosus, semitendinosus, infraspinatus, and supraspinatus). Eight mature blesbok were harvested per season (winter and spring). Gender and muscle type influenced (p b 0.05) the fatty acid profiles of blesbok muscles, while season only influenced the C18:3ω3 (α-linolenic acid, ALA) percentages and therefore the total omega-3 poly-unsaturated fatty acids (total ω3 PUFA). Female muscles had higher C16:0 (palmitic acid) (21.01% ± 0.256 vs. 19.05% ± 0.296) and total MUFA percentages, while male muscles had higher (p b 0.05) C18:2ω6c, C20:5ω3, total ω3 PUFA (11.08% ± 0.382 vs. 8.50% ± 0.367), and total PUFA (43.03% ± 0.904 vs. 29.59% ± 1.164) percentages, contributing to higher poly-unsaturated to saturated fatty acid ratios (PUFA:SFA ratios). Differences in fatty acid profiles were attributed more to gender and anatomical location of muscles, than seasonal differences in diets. © 2014 Elsevier Ltd. All rights reserved.

1. Introduction Red meat consumers primarily use the visible fat (intra- and intermuscular) (Hoffman, Muller, Schutte, Calitz, & Crafford, 2005) and nutritional claims on packaging as an indication of the healthiness of meat products (Issanchou, 1996). When considering the nutritional value of meat containing fat, three factors are important: the total fat content; the PUFA:SFA ratio; and the omega-6 to omega-3 fatty acid ratio (ω6:ω3) (Enser et al., 1998). However, the healthiness and sensory properties of meat are also determined by the overall fatty acid profile (Hocquette et al., 2010). The meat industry has been successful in reducing the fat content and modifying the fatty acid profile of red meats in accordance with the demands by health conscious consumers (Higgs, 2000; Van Schalkwyk & Hoffman, 2010; Warriss, 2000). Decreases in the fat content of game meat is, however, not necessary since the fat content is known to be very low (2–3%) (Aidoo & Haworth, 1995; Van Schalkwyk & Hoffman, 2010). Difficulty also exists in modifying the fatty acid profile of meat from ruminant animals, since PUFA from forage are hydrogenated in the rumen to less unsaturated or saturated fatty acids (SFAs) (Warriss,

⁎ Corresponding author at: Department of Animal Sciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa. Tel.: + 27 21 808 4747; fax: + 27 21 808 4750. E-mail address: [email protected] (L.C. Hoffman).

http://dx.doi.org/10.1016/j.meatsci.2014.06.030 0309-1740/© 2014 Elsevier Ltd. All rights reserved.

2000; Wood & Enser, 1997). Meat from ruminants will therefore have correspondingly lower PUFA:SFA ratios (Enser et al., 1998; Wood & Enser, 1997) as well as lower ω6:ω3 (especially in strictly grazing ruminants) (Enser et al., 1998). The fatty acid profiles of game meat has similarities with other red meat types, since the main fatty acids in the meat are usually C16:0 (palmitic acid), C18:0 (stearic acid) and C18:1ω9 (oleic acid) (Aidoo & Haworth, 1995). Fatty acid profiles can differ between genders, as the muscles from female animals often have higher quantities of intramuscular fat (Lawrie & Ledward, 2006). Blesbok (Damaliscus pygargus phillipsi) is a popular game species hunted and consumed in South Africa. It is a free-ranging species that grazes selectively on short grass species (Bothma, Van Rooyen, & Du Toit, 2010; Du Plessis, 1972). Blesbok generally have regional and seasonal differences in the grass species available to them, as well as seasonal preferences towards specific grass species (Skinner & Chimimba, 2005). The composition of the forage consumed generally influences the quantity and quality of the fat present in the meat from ruminant animals (Warriss, 2000). Differences in the plane of nutrition and activity level are known to influence the fibre type composition of skeletal muscles (Lawrie & Ledward, 2006) subsequently causing variations in fatty acid profiles (Wood et al., 2003). Research on the factors influencing the chemical composition of the meat from various game species is usually limited to the longissimus thoracis et lumborum (LTL) (Hoffman, Kroucamp, & Manley, 2007; Hoffman, Mostert, Kidd, & Laubscher, 2009; Hoffman, Smit, & Muller, 2008; Hoffman, Van Schalkwyk, & Muller, 2008;

600

J. Neethling et al. / Meat Science 98 (2014) 599–606

Hoffman, Van Schalkwyk, & Muller, 2009; Purchas, Triumf, & Egelandsdal, 2010), since the commercial red meat industry considers the LTL to be the most representative muscle in domestic livestock carcasses (Warriss, 2000). This study was therefore aimed at quantifying the impact of season on the fatty acid profiles of six commercially important blesbok muscles from male and female animals. 2. Materials and methods 2.1. Harvesting of blesbok Blesbok were harvested on Brakkekuil farm (34°18′24.0″S and 20°49′3.9″E; 93 m.a.s.l.), near Witsand, Western Cape Province, South Africa. The study area is classified as the Coastal Renosterveld and receives 300–500 mm of non-seasonal rainfall (Chase & Meadows, 2007; Kruger, 2007; Rebelo, Boucher, Helme, Mucina, & Rutherford, 2006; Rutherford, Mucina, & Powrie, 2006). Eight mature blesbok were harvested per season in June (winter) and October (spring) of 2010. The harvesting periods formed part of the general management strategies of the farm and therefore no preference was given to the selection of male or female blesbok (winter, three males and five females; spring, four males and four females); in addition both genders have horns and it is difficult to distinguish between the two sexes at a distance. The blesbok were harvested during the day and shot in the head or the high neck area with a .308 calibre rifle, so as to cause immediate death. No unnecessary ante mortem stress was experienced by the animals (ethical clearance number: 10NP_HOF02, issued by Stellenbosch University Animal Care and Use Committee). Exsanguination occurred within 2 min while in the field. Partially dressed carcasses were transported to slaughtering facilities where the head, legs and skin were removed and evisceration occurred according to the Draft Meat Safety Act, 2000 (Act No. 40 of 2000). 2.2. Sample preparation The dressed carcasses were cooled (0°–5 °C) shortly after dressing (≈45 min post mortem). After 24 h the longissimus thoracis et lumborum (LTL), biceps femoris (BF), semimembranosus (SM), semitendinosus (ST), infraspinatus (IS) and supraspinatus (SS) muscles were removed completely from the left side of each carcass. Muscles were weighed, homogenised, vacuum-packed and stored at − 20 °C. Approximately four weeks after harvesting, the homogenised muscle samples were removed and thawed for 12 h at ≈4 °C, prior to fatty acid analyses. 2.3. Intramuscular fatty acids Two grammes of each sample was extracted according to a method by Folch, Lees, and Sloane Stanley (1957). Extractions were performed with a chloroform:methanol (2:1; v/v) solution containing 0.01% butylated hydroxytoluene (BHT) as antioxidant. Samples were homogenised for 30 s in the extraction solvent, by use of a polytron mixer (WiggenHauser, D-500 Homogenizer). To enable quantification of the individual fatty acids in the original muscle sample, heptadecanoic acid (C17:0) was used as an internal standard. A sub-sample was taken from the extracted fats and transmethylated for 2 h at 70 °C with a methanol:sulphuric acid (19:1; v/v) solution. The sub-sample was cooled to room temperature after which the resulting fatty acid methyl esters (FAME) were extracted with the use of water and hexane. The top hexane phase was transferred to a spotting tube and dried under nitrogen. Fifty microlitres of hexane was added to the dried sample of which 1 μl was injected. The FAME were analysed by gas–liquid chromatography (Varian Model 3300 equipped with a flame ionisation detector) using a 60 m BPX70 capillary column of 0.25 mm internal diameter (SGE International Pty Ltd, 7 Argent Place, Ringwood, Victoria 3134, Australia). The hydrogen gas flow rate was 25 ml·min−1 and the hydrogen carrier

gas flow rate was 2–4 ml·min−1. Temperature programming was linear at 3.4 °C·min−1 with the following temperature settings: initial temperature of 60 °C; final temperature of 160 °C; injector temperature of 220 °C; and detector temperature of 260 °C. The run time was ≈45 min with an injection volume of 1 μl. The FAME in the total lipids of each sample (mg·g−1 sample) were identified by comparing the retention times with those of a standard FAME mixture (Supelco™ 37 Component FAME Mix, 10 mg·ml−1 in CH2Cl2, Catalogue Number 47885-U. Supelco™, North Harrison Road, Bellefonte, PA 16823-0048, USA). The fatty acid profile was calculated and compared as a proportion of the total amount of fatty acids present in each sample. 2.4. Statistical analysis Statistical analysis of data was performed using the Statistica 10 VEPAC module (STATISTICA, 2011). The mixed model repeated measures of analysis of variance (ANOVA) was conducted with animal as random factor nested in the fixed season and gender effects. Muscle type, also a fixed effect, was treated as a within subject effect. The total intramuscular fat percentage was also added as a covariate of the fatty acid percentage data. Fisher LSD was used for post hoc testing. Normal probability plots were continuously checked for deviations from normality and possible outliers. A 5% significance level was used as guideline for determining significant effects. Most of the values are reported as the Means and Standard Error of the Mean (SEM). Pearson correlations were used to test for relationships between measured variables. 3. Results Table 1 depicts the differences in carcass weights (kg) and mean intramuscular fat percentages (means ± SD) of six blesbok muscles for both genders and seasons, as well as the respective p-values. It should be noted that this data refers to a previous publication by Neethling et al. (2014). Table 2 depicts the nature of the significant interactions (p-values) between the main effects (season, gender and muscle type) and the individual impact of each effect on the fatty acid profile of blesbok meat. The overall means and standard deviations of the fatty acid profile (g·100 g−1 total fatty acids) of blesbok meat (all muscles and seasons) are included in Table 2, so as to provide some insight into the importance of each fatty acid. Since the aim of the study was to quantify the impact of season, gender and muscle type on the fatty acid profile of blesbok meat, the results are discussed as percentage values (% fatty acid of all identified fatty acids within the intramuscular fat), rather than mg·g−1 of meat (fatty acid content), as the fatty acid content can vary with varying intramuscular fat content (as a result of significant differences or interactions between the main factors). The interactions depicted in Table 2 are only relevant to the g·100 g−1 total fatty acid values. The level of statistical significance (p-values) for the fatty acid calculated with intramuscular fat as a co-variant was also added to Table 2, however, due to the small changes in the p-values this will not be discussed further. The column with the mg·g−1 fatty acid values is for the LTL only (most representative muscle) and these values were added for nutritional tabulation purposes and will not be discussed further. The overall intramuscular fat percentages of blesbok meat from this study area were low (b 3 g·100 g−1 meat; Neethling et al., 2014), as is generally the case for wild and free-living South African game species (Aidoo & Haworth, 1995; Ramanzin et al., 2010; Van Schalkwyk & Hoffman, 2010). The fatty acids present in very low percentages (≤1%) will therefore not be discussed further in detail. The impact of the three-way interaction between the main effects (season, gender and muscle type) on the percentages of C20:3ω6 (homo-g-linolenic acid), C20:4ω6 (arachidonic acid), omega-3 polyunsaturated fatty acids (ω6 PUFAs) and ω6:ω3, is presented in Table 3. The homo-g-linolenic acid, arachidonic acid and ω6 PUFA percentages of male muscles from both harvesting seasons were higher (p b 0.05)

J. Neethling et al. / Meat Science 98 (2014) 599–606

601

Table 1 Mean values for the carcass weights (kg) and intramuscular fat percentages (IMF %) (means ± SD) of male and female blesbok from two seasons.

Carcass weight IMF %

Winter

Spring

p value*

Male

Female

p value**

27.06 ± 3.89 2.64 ± 0.46

25.24 ± 4.62 2.54 ± 0.48

0.43 0.73

25.83 ± 4.95 2.36 ± 0.31

26.55 ± 3.73 2.77 ± 0.50

0.83 0.07

IMF %, Mean intramuscular fat percentage of six muscles (thoracis et lumborum, biceps femoris, semimembranosus, semitendinosus, infraspinatus and supraspinatus); *, p-value for season; **, p-value for gender (Neethling, Hoffman, & Britz, 2014).

than female muscles (Table 3). These gender differences were greater in the muscles from winter compared to spring. The homo-g-linolenic acid, arachidonic acid and ω6 PUFA percentages of the SS from male animals were higher (p b 0.05) in winter, compared to spring (Table 3). The ω6:ω3 was higher (p b 0.05) for male and female muscles from winter, compared to spring. Table 4 depicts the nature of the two-way significant interactions between gender and muscle type for C18:1ω9c (oleic acid), total mono-unsaturated fatty acids (total MUFAs) and the poly-unsaturated to saturated fatty acid ratios (PUFA:SFA ratios). The muscles from female animals had higher (p b 0.05) oleic acid and total MUFA percentages, but lower (p b 0.05) PUFA:SFA ratios. Oleic acid and total MUFA percentages were significantly higher in the ST and IS, but lowest (p b 0.05) in the LD and SM of the muscles from female animals (Table 4). In contrast, differences in oleic acid and total MUFA percentages between the muscles from male animals were less pronounced (Table 4). The PUFA:SFA ratios of the LTL, BF and ST from male animals were higher (p b 0.05) compared to the SM, IS and SS (Table 4). The LTL from female animals had the highest PUFA:SFA ratios, whereas these were lowest (p b 0.05) in the IS and SS (Table 4). Table 5 depicts the nature of the significant two-way interactions between season and muscle type for the oleic acid and total MUFA percentages. The oleic acid and total MUFA percentages were higher (p ≥ 0.05) in the muscles from spring, with greater differences (p ≥ 0.05) for the ST, IS and SS (Table 5). The difference in oleic acid and total MUFA percentages between muscles was smaller (p ≥ 0.05) in winter, whereas in spring, the LD, BF and SM had the lowest (p b 0.05) oleic acid and total MUFA percentages (Table 5). The effect of muscle type on the fatty acid percentages of blesbok meat is presented in Table 6. The C16:0 (palmitic acid), C18:0 (stearic acid) and total saturated fatty acid (total SFA) percentages were higher (p b 0.05) in the SM, IS and SS muscles. The LTL had the highest (p b 0.05) C18:2ω6c (linoleic acid) and C18:3ω3 (α-linolenic acid, ALA) percentages, while the forequarter muscles (IS and SS) had the lowest (p b 0.05) percentages (Table 6). The IS and SS also had the lowest (p b 0.05) percentages of C20:5ω3 (eicosapentaenoic acid, EPA) and C22:5ω3 (docosapentaenoic acid) (Table 6). The total omega-3 poly-unsaturated fatty acids (ω3 PUFAs) and thus total PUFA were also lowest in the IS and SS, but highest in the LTL (Table 6). The effect of gender on the fatty acid percentages of blesbok meat is presented in Table 7. Female muscles had higher (p b 0.05) percentages of palmitic acid, while male muscles had higher (p b 0.05) percentages of C16:1ω9, linoleic acid, EPA, total ω3 PUFA and total PUFA (Table 7). Table 8 depicts the nature of the significant impact of season on the fatty acid percentages of blesbok meat. The blesbok meat from spring had higher (p b 0.05) percentages of ALA and total ω3 PUFA (Table 8). 4. Discussion Skeletal muscles are generally unique, heterogeneous combinations of different muscle fibre types (Cassens & Cooper, 1971; Taylor, 2004). Oxidative muscle fibres (Type I) mainly utilise fat as an energy source, while the glycolytic muscle fibres (Type IIB) mainly utilise stored glycogen or glucose as energy sources (Cassens & Cooper, 1971; Kohn, Kritzinger, Hoffman, & Myburgh, 2005; Taylor, 2004). In blesbok, the LTL is mostly utilised for the maintenance of posture (balance and stability) (Robert, Audigié, Valette, Pourcelot, & Denoix, 2001), while the

hindquarter muscles (BF, SM and ST) and forequarter muscles (IS and SS) are utilised during the former as well as for walking while grazing and running when threatened (Du Plessis, 1972; Kohn et al., 2005; Lynch, 1971). It is expected that the muscle fibre type compositions of the selected blesbok muscles would differ in accordance with their anatomical locations and consequently the fatty acid profiles would also differ (Wood et al., 2003). Aidoo and Haworth (1995) identified the main fatty acids in red meat as palmitic, stearic and oleic acids. Palmitic acid together with C14:0 (myristic acid) is the main SFA responsible for raising the lowdensity lipoprotein (LDL) serum cholesterol concentrations in humans (Daley, Abbott, Doyle, Nader, & Larson, 2010; Katan, Zock, & Mensink, 1994; Schönfeldt & Gibson, 2008), ultimately increasing the risk for coronary diseases (Jansen van Rensburg, 2002). The SM and forequarter muscles had the highest (p b 0.01) percentages of palmitic and stearic acids (Table 6). Palmitic and stearic acids were the main SFAs contributing to the total SFA percentage in blesbok meat (Table 2), consequently contributing to the higher total SFA percentages in the SM and forequarter muscles (Table 6). Palmitic acid was also present at significantly higher percentages in female muscles (Table 7), but gender did not influence the total SFA percentages (Table 2). Alpha-linolenic acid and linoleic acid are essential fatty acids, which are not synthesized in the body and should therefore be consumed in the diet (Bézard, Blond, Bernard, & Clouet, 1994). These two essential fatty acids are precursors for the longer chained ω6 PUFA and ω3 PUFA (Spector, 2006). The total lipid content of grass is normally low (McDonald, Edwards, Greenhalgh, & Morgan, 2002), nonetheless, the main fatty acids in grass are ALA (60–75% of total fatty acids) and to a lesser extent linoleic and palmitic acids (Khan, Cone, Fievez, & Hendriks, 2012; McDonald et al., 2002). The fatty acid profile can, however, be unique for different grass species (Dewhurst, Scollan, Youell, Tweed, & Humphrey, 2001). The blesbok muscles from spring had the highest (p b 0.01) ALA percentages compared to those from winter and consequently contributed to significantly higher ω3 PUFA percentages in blesbok meat from spring (Table 8). The ALA percentage and so the total lipid percentage in grass is high during the primary growth stage (spring), but decreases with maturation (Khan et al., 2012). Since blesbok are strict grazers (Du Plessis, 1972), it was expected that those harvested in spring, would have higher total lipid and thus ALA percentages in the meat. Such results were found by Dewhurst et al. (2001) when the total lipid content of winter and spring samples of three ryegrass species was compared. The ω6:ω3 was higher in winter, compared to spring (Table 3), which could also be attributed to an increase in the ω3 fatty acid content in the diet of the blesbok in spring, consequently lowering the ω6:ω3 in the meat. It is, however, unclear why the SS from male animals was the only muscle greatly affected (p b 0.05; Table 3) by the seasonal difference in fatty acid content of the blesbok diet. Linoleic acid and ALA contributed the highest percentage of the ω6 PUFA and ω3 PUFA, respectively (Table 2). Both these fatty acids were present at highest (p b 0.01) percentages in the LTL and lowest (p b 0.01) in the forequarter muscles (Table 6). As EPA is a longer and more unsaturated fatty acid converted from ALA, it was also present at highest (p b 0.01) percentages in the LTL (together with the BF and ST) and lowest (p b 0.01) in the forequarter muscles (Table 6). The LTL therefore contained the highest (p b 0.01) and the forequarter muscles the lowest (p b 0.01) percentages of total ω3 PUFAs (Table 6).

602

J. Neethling et al. / Meat Science 98 (2014) 599–606

Table 2 Level of statistical significance (p-values) for interactions between main effects and the main effects (season, gender and muscle type) on the fatty acid profile (g·100 g−1 total fatty acids) of male and female blesbok muscles; mean values for the fatty acid profile of male and female blesbok muscles (means ± SD); level of statistical significance for the fatty acid calculated with intramuscular fat as a co-variant*; and mean values for fatty acid content (mg fatty acids/g meat) of blesbok LTL (means ± SD). Fatty acid composition

S×G×M

G×M

S×M

S×G

Muscle

Gender

Season

C14:0 C14:0* C15:0 C15:0* C16:0 C16:0* C18:0 C18:0* C20:0 C20:0* C21:0 C21:0* C22:0 C22:0* C24:0 C24:0* C14:1 C14:1* C15:1 C15:1* C16:1ω9 C16:1ω9* C18:1ω9c C18:1ω9c* C18:1ω9t C18:1ω9t* C20:1ω9 C20:1ω9* C22:1ω9 C22:1ω9* C24:1ω9 C24:1ω9* C18:2ω6c C18:2ω6c* C18:2ω6t C18:2ω6t* C18:3ω6 C18:3ω6* C18:3ω3 C18:3ω3* C20:2 C20:2* C20:3ω6 C20:3ω6* C20:3ω3 C20:3ω3* C20:4ω6 C20:4ω6* C20:5ω3 C20:5ω3* C22:2ω6 C22:2ω6* C22:5ω3 C22:5ω3* C22:6ω3 C22:6ω3*

0.03 0.07 0.05 0.07 0.07 0.15 0.29 0.48 0.15 0.16 0.61 0.77 0.10 0.15 0.44 0.68 0.12 0.25 0.08 0.09 0.06 0.06 0.62 0.71 0.59 0.67 0.51 0.59 0.52 0.71 0.31 0.35 0.09 0.21 0.31 0.47 0.17 0.23 0.49 0.63 0.63 0.67 b0.01 0.02 0.59 0.87 0.03 0.08 0.11 0.19 0.90 0.26 0.43 0.56 0.15 0.03

0.06 0.13 0.11 0.10 0.27 0.13 0.77 0.29 0.03 0.03 0.04 0.33 b0.01 0.06 0.21 0.17 0.11 b0.01 0.18 0.13 0.10 0.10 b0.01 b0.01 0.69 0.38 0.23 0.28 0.19 0.60 0.72 0.70 0.08 0.11 0.85 0.17 0.02 0.09 0.23 0.17 0.07 0.05 0.02 0.01 0.91 0.58 0.02 0.03 0.05 0.01 0.01 b0.01 0.87 0.55 0.48 0.06

1.00 0.91 0.67 0.62 1.00 0.86 0.17 0.15 0.30 0.31 0.38 0.23 0.01 0.14 0.52 0.97 0.85 0.97 0.67 0.56 0.42 0.43 b0.01 0.06 0.32 0.48 0.08 0.04 0.88 0.75 0.44 0.26 0.29 0.64 0.08 0.10 0.08 0.14 0.15 0.34 0.14 0.12 0.01 0.05 0.27 0.40 0.11 0.40 0.31 0.41 0.97 0.39 0.80 0.85 0.16 0.30

0.98 0.22 0.70 0.56 0.75 0.28 0.21 0.03 0.41 0.43 0.73 0.31 0.89 0.74 0.70 0.98 0.51 0.07 0.33 0.43 0.69 0.75 0.84 0.98 0.30 0.04 0.05 0.17 0.63 0.80 0.12 0.02 0.46 0.12 0.96 0.53 0.15 0.15 0.08 0.07 0.03 0.05 0.40 0.17 0.54 0.92 0.38 0.05 0.82 0.90 0.64 0.04 0.98 0.62 0.59 0.65

b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 0.01 b0.01 0.51 0.50 0.12 0.05 b0.01 b0.01 b0.01 b0.01 0.25 0.24 b0.01 b0.01 b0.01 b0.01 0.38 0.17 0.08 0.17 0.04 0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 0.14 0.20 b0.01 b0.01 0.01 b0.01 b0.01 b0.01 b0.01 b0.01 0.04 b0.01 0.02 0.03 b0.01 b0.01

b0.01 b0.01 0.74 0.48 0.02 0.05 0.14 0.56 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 0.25 0.79 0.01 0.01 b0.01 b0.01 b0.01 b0.01 0.01 0.02 0.08 0.40 b0.01 0.01 b0.01 b0.01 b0.01 b0.01 0.54 0.81 0.20 0.27 0.09 0.14 0.62 0.37 b0.01 0.01 0.01 0.02 b0.01 b0.01 b0.01 0.01 b0.01 b0.01 0.12 0.37 0.02 0.02

0.54 0.52 0.58 0.63 0.09 0.03 0.91 0.91 b0.01 b0.01 0.48 0.24 0.86 0.63 0.01 b0.01 0.56 0.41 0.03 0.04 0.28 0.30 0.41 0.31 0.12 0.02 0.54 0.04 0.90 0.98 0.03 0.01 0.18 0.04 b0.01 b0.01 0.71 0.73 b0.01 b0.01 b0.01 0.01 0.22 0.10 0.03 0.01 0.51 0.21 0.32 0.26 0.52 0.05 0.19 0.17 0.38 0.22

Fatty acid totals SFA SFA* MUFA MUFA* PUFA PUFA* ω6 PUFA ω6 PUFA* ω3 PUFA ω3 PUFA*

0.08 0.19 0.61 0.71 0.07 0.19 0.04 0.09 0.30 0.41

0.61 0.17 b0.01 b0.01 0.07 0.04 0.02 0.03 0.37 0.12

0.45 0.33 b0.01 0.05 0.23 0.61 0.17 0.50 0.51 0.70

0.35 0.04 0.81 0.95 0.72 0.28 0.43 0.09 0.39 0.45

b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01

0.05 0.18 b0.01 b0.01 b0.01 b0.01 b0.01 b0.01 0.04 0.06

0.38 0.30 0.44 0.33 0.98 0.79 0.25 0.06 b0.01 b0.01

Fatty acid ratios PUFA:SFA PUFA:SFA* ω6:ω3 ω6:ω3*

0.06 0.16 0.01 0.02

0.04 b0.01 b0.01 b0.01

0.27 0.66 b0.01 b0.01

0.59 0.16 b0.01 b0.01

b0.01 b0.01 b0.01 b0.01

b0.01 b0.01 b0.01 b0.01

0.88 0.99 b0.01 b0.01

g·100 g−1 total fatty acids for all muscles

mg·g−1 meat for LTL

0.92 ± 0.437

0.17 ± 0.119

0.51 ± 0.132

0.10 ± 0.031

20.16 ± 2.124

5.00 ± 1.135

25.54 ± 3.406

6.10 ± 1.284

0.09 ± 0.022

0.02 ± 0.005

0.12 ± 0.036

0.04 ± 0.006

0.13 ± 0.043

0.03 ± 0.007

0.22 ± 0.123

0.06 ± 0.022

0.20 ± 0.066

0.04 ± 0.014

0.37 ± 0.064

0.09 ± 0.020

1.05 ± 0.210

0.28 ± 0.048

14.38 ± 6.420

3.39 ± 1.757

0.22 ± 0.059

0.05 ± 0.022

0.14 ± 0.052

0.03 ± 0.005

0.18 ± 0.057

0.05 ± 0.010

0.15 ± 0.050

0.05 ± 0.014

16.16 ± 4.851

5.00 ± 1.071

0.15 ± 0.047

0.03 ± 0.009

0.28 ± 0.080

0.09 ± 0.017

4.63 ± 1.546

1.37 ± 0.307

0.09 ± 0.020

0.02 ± 0.006

1.27 ± 0.554

0.34 ± 0.134

0.12 ± 0.036

0.03 ± 0.007

7.74 ± 2.595

2.16 ± 0.562

2.00 ± 0.691

0.59 ± 0.130

0.30 ± 0.171

0.07 ± 0.019

2.52 ± 0.873

0.71 ± 0.203

0.36 ± 0.152

0.10 ± 0.025

47.69 ± 5.397

11.54 ± 2.485

16.47 ± 6.240

3.93 ± 1.754

35.47 ± 10.027

10.49 ± 2.052

25.75 ± 7.895

7.65 ± 1.713

9.63 ± 2.890

2.80 ± 0.544

0.77 ± 0.283

0.96 ± 0.286

2.75 ± 0.720

2.76 ± 0.589

J. Neethling et al. / Meat Science 98 (2014) 599–606

603

Table 3 Impact of the three-way interaction between the main effects (season, gender and muscle type) on C20:3ω6, C20:4ω6, ω6 PUFA (gº100 g−1 of total fatty acids) and the ω6:ω3 (means ± SEM). Longissimus thoracis et lumborum C20:3ω6 Winter 2010 Male Female Spring 2010 Male Female C20:4ω6 Winter 2010 Male Female Spring 2010 Male Female ω6 PUFA Winter 2010 Male Female Spring 2010 Male Female ω6:ω3 Winter 2010 Male Female Spring 2010 Male Female

Biceps femoris

Semimembranosus

Semitendinosus

Infraspinatus

Supraspinatus

1.87ab ± 0.204 0.96fe ± 0.270

1.93a ± 0.256 1.07fd ± 0.154

1.21fc ± 0.615 1.23fb ± 0.117

2.12a ± 0.109 1.08fd ± 0.161

1.83ab ± 0.290 1.08fd ± 0.187

2.06a ± 0.164 0.95fe ± 0.158

1.63abcd ± 0.109 1.05fd ± 0.131

1.70abc ± 0.170 1.10fc ± 0.123

1.52abcde ± 0.140 0.94fe ± 0.161

1.71abc ± 0.146 1.01fd ± 0.186

0.82f ± 0.491 0.88fe ± 0.122

1.13f ± 0.383 0.88fe ± 0.181

10.87abc ± 0.564 6.77hgk ± 0.650

11.10ab ± 1.131 6.02hik ± 0.769

9.70ecf ± 0.869 6.76hgk ± 0.522

11.96a ± 0.474 5.94hik ± 0.795

9.41edf ± 1.136 5.34li ± 0.772

10.76abc ± 0.430 4.77lj ± 0.691

10.22acd ± 0.376 6.84hgij ± 1.107

10.39acd ± 0.705 7.33efgi ± 1.047

9.16eb ± 0.651 6.02hl ± 1.138

10.28acd ± 0.519 6.46hgij ± 1.291

8.64ebfg ± 0.611 5.06lk ± 0.843

7.90hf ± 0.431 5.02lk ± 1.043

37.51ab ± 2.299 25.89fehk ± 2.963

35.61abc ± 3.950 21.63mij ± 3.168

30.99fdeh ± 3.414 23.43mh ± 2.288

37.60ab ± 2.029 20.38ljn ± 3.054

31.93fcd ± 3.959 19.36ljn ± 3.053

35.16abc ± 1.529 18.02ln ± 2.839

34.52ad ± 0.871 24.35flghi ± 2.743

32.03abde ± 1.652 23.72flghi ± 2.747

28.31fchi ± 1.823 19.42mjkn ± 3.237

31.13bceg ± 1.483 20.43mjkn ± 3.452

26.32fhij ± 1.445 17.41mn ± 2.193

25.58fhij ± 1.610 17.35mn ± 2.766

3.63bc ± 0.367 2.93de ± 0.135

3.72bc ± 0.016 2.92de ± 0.194

3.54c ± 0.191 2.76fe ± 0.166

3.83b ± 0.091 2.74feg ± 0.119

4.51a ± 0.219 3.00d ± 0.136

4.46a ± 0.149 2.91de ± 0.109

2.39hgi ± 0.082 2.27hk ± 0.067

2.40hg ± 0.106 2.17hj ± 0.091

2.15jk ± 0.056 1.97j ± 0.054

2.33hj ± 0.153 2.11hj ± 0.083

2.33hj ± 0.105 2.01ji ± 0.102

2.43fh ± 0.065 2.08hj ± 0.093

a–n

Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05) between seasons, genders and/or muscle types for a fatty acid or fatty acid ratio; ω6 PUFA, omega-6 polyunsaturated fatty acids = sum of C18:2ω6c, C18:3ω6, C20:3ω6, C20:4ω6 and C22:2ω6; ω6:ω3, omega-6 to omega-3 polyunsaturated fatty acids ratio = [(sum of C18:2ω6c, C18:3ω6, C20:3ω6, C20:4ω6 and C22:2ω6)/(sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3)]; SEM, standard error of the mean; longissimus thoracis et lumborum, LTL; biceps femoris, BF; semimembranosus, SM; semitendinosus, ST; infraspinatus, IS; and supraspinatus, SS.

Muscles with higher proportions of oxidative fibres will generally have higher quantities of phospholipids and thus higher quantities of total PUFA (Spector, 2006; Wood et al., 2003). It was believed that blesbok LTL had the highest proportions of oxidative muscle fibres, as a result of lower activity levels compared to the five other muscles. The PUFA:SFA ratios were also highest (p b 0.05) in LTL, but lowest in the forequarter muscles (both genders) and SM (male muscles) (Table 4), which is again attributable to the higher and lower percentages of precursor ω3 and ω6 PUFAs (linoleic acid and ALA) in these muscles, respectively (Table 6). Oleic acid is usually the most abundant MUFA and therefore contributes greatest to the total MUFA percentage in meat (Spector, 2006). All muscles from female animals had higher (p b 0.01) oleic acid percentages compared to the muscles from male animals (Table 4). The total MUFA percentages were therefore also higher (p b 0.01) in all female muscles (Table 4). Female blesbok muscles can therefore be considered healthier for human consumption, as oleic acid, together with linoleic

acid and C20:4ω6 (arachidonic acid) is known for its cholesterollowering properties (Schönfeldt & Gibson, 2008). The muscles from male animals contained higher (p b 0.01) percentages of linoleic acid (Table 7) and therefore also contained higher percentages of the longer, more unsaturated ω6 PUFAs (C20:3ω6 and C20:4ω6) and total ω6 PUFAs (Table 3). The muscles from male animals also contained higher (p b 0.05) total ω3 PUFAs (Table 7), and together with their lower (p b 0.05) palmitic acid percentages (Table 7), resulted in higher PUFA:SFA ratios in male blesbok muscles (Table 4). Similar results for differences in fatty acid profiles between genders have been established for other game species; the longissimus lumborum (LL) from female kudu (Tragelaphus strepsiceros) has higher (p ≥ 0.05) total SFA and MUFA percentages, while LL from male kudu has higher total PUFA percentages (Mostert & Hoffman, 2007). Hoffman, Kritzinger and Ferreira (2005) established that LL from predominantly grazing female impala (Aepyceros melampus) had higher total SFA (p b 0.05) and MUFA (p ≥ 0.05) percentages, whereas total PUFA percentages were

Notes to Table 2 S × G × M, interaction between harvesting season (S), gender (G) and muscle type (M; longissimus thoracis et lumborum, biceps femoris, semimembranosus, semitendinosus, infraspinatus and supraspinatus); G × M, interaction between gender (G) and muscle type (M); S × M, interaction between harvesting season (S) and muscle type (M); S × G, interaction between harvesting season (S) and gender (G); SD, Standard Deviation; LTL, longissimus thoracis et lumborum; SFA, sum of saturated fatty acids = sum of C14:0, C15:0, C16:0, C18:0, C20:0, C21:0, C22:0 and C24:0; MUFA, mono-unsaturated fatty acids = sum of C14:1, C15:1, C16:1ω9, C18:1ω9c, C20:1ω9, C22:1ω9 and C24:1ω9; PUFA, polyunsaturated fatty acids = sum of C18:2ω6c, C18:3ω6, C18:3ω3, C20:2, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3 and C22:6ω3; ω3 PUFA, omega-3 polyunsaturated fatty acids = sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3; ω6 PUFA, omega-6 polyunsaturated fatty acids = sum of C18:2ω6c, C18:3ω6, C20:3ω6, C20:4ω6 and C22:2ω6; PUFA:SFA ratio, polyunsaturated to saturated fatty acids ratio = [(sum of C18:2ω6c, C18:3ω6, C18:3ω3, C20:2, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3 and C22:6ω3)/(sum of C14:0, C15:0, C16:0, C18:0, C20:0, C21:0, C22:0 and C24:0)]; ω6:ω3, omega-6 to omega-3 polyunsaturated fatty acids ratio = [(sum of C18:2ω6c, C18:3ω6, C20:3ω6, C20:4ω6 and C22:2ω6)/(sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3)]; *, p-values with intramuscular fat (IMF) as a covariant of the percentage fatty acid values. Statistical significance b 0.05 is indicated in bold. The IMF had a significant impact on the following fatty acid percentages: C14:0, C16:0, C18:0, C21:0, C22:0, C24:0, C14:1, C18:1ω9c, C18:1ω9t, C22:1ω9, C24:1ω9, C18:2ω6c, C18:2ω6t, C18:3ω3, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3, C22:6ω3, SFA, MUFA, PUFA, ω6 PUFA, ω3 PUFA, and PUFA:SFA.

604

J. Neethling et al. / Meat Science 98 (2014) 599–606

Table 4 Impact of the two-way interaction between gender and muscle type on C18:1ω9c, total MUFA (g·100 g−1 of total fatty acids) and the PUFA:SFA ratio (means ± SEM). Longissimus thoracis et lumborum

Biceps femoris

C18:1ω9c Male Female

8.02e ± 0.561 16.34c ± 1.508

8.51e ± 0.579 18.67b ± 1.941

Total MUFA Male Female

10.27e ± 0.534 18.27c ± 1.462 1.19a ± 0.037 0.78c ± 0.082

PUFA:SFA Male Female

Semimembranosus

Semitendinosus

Infraspinatus

Supraspinatus

8.96de ± 0.545 17.00c ± 1.349

8.23e ± 0.733 20.93a ± 2.412

10.39d ± 0.673 20.38a ± 1.694

9.07de ± 1.142 18.68b ± 1.422

10.74e ± 0.571 20.53b ± 1.938

11.47de ± 0.572 18.87c ± 1.328

10.62e ± 0.658 22.81a ± 2.442

12.71d ± 0.645 22.34a ± 1.656

11.34de ± 1.064 20.64b ± 1.415

1.06b ± 0.084 0.69cd ± 0.085

0.87c ± 0.072 0.64d ± 0.070

1.07b ± 0.049 0.62d ± 0.078

0.80cd ± 0.063 0.52e ± 0.055

0.81cd ± 0.063 0.47e ± 0.058

a–e

Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05) between genders and/or muscle types for a fatty acid, fatty acid total or fatty acid ratio; MUFA, mono-unsaturated fatty acids = sum of C14:1, C15:1, C16:1ω9, C18:1ω9c, C20:1ω9, C22:1ω9 and C24:1ω9; PUFA:SFA ratio, polyunsaturated to saturated fatty acid ratio = [(sum of C18:2ω6c, C18:3ω6, C18:3ω3, C20:2, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3 and C22:6ω3)/(sum of C14:0, C15:0, C16:0, C18:0, C20:0, C21:0, C22:0 and C24:0)]; SEM, standard error of the mean; longissimus thoracis et lumborum, LTL; biceps femoris, BF; semimembranosus, SM; semitendinosus, ST; infraspinatus, IS; and supraspinatus, SS.

Table 5 Impact of the two-way interaction between season and muscle type on C18:1ω9c and total MUFA (g·100 g−1 of total fatty acids) (means ± SEM). Longissimus thoracis et lumborum

Biceps femoris

Semimembranosus

Semitendinosus

Infraspinatus

Supraspinatus

C18:1ω9c Winter 2010 Spring 2010

12.84ec ± 1.927 12.56ed ± 2.075

14.50ae ± 2.496 13.96ed ± 2.472

13.74eb ± 1.840 13.23ed ± 1.926

14.53ae ± 2.922 16.21abc ± 3.238

15.62ad ± 2.275 16.41ab ± 2.414

13.27ec ± 2.306 15.69abc ± 2.082

Total MUFA Winter 2010 Spring 2010

15.00ec ± 1.865 14.55ed ± 1.992

16.56ae ± 2.466 15.94ed ± 2.389

15.98ae ± 1.748 15.29ed ± 1.812

16.57ae ± 2.852 18.39abc ± 3.173

17.77ad ± 2.200 18.48ab ± 2.340

15.43eb ± 2.235 17.70abc ± 2.036

a–e Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05) between seasons and/or muscle types for a fatty acid or fatty acid total; MUFA, mono-unsaturated fatty acids = sum of C14:1, C15:1, C16:1ω9, C18:1ω9c, C20:1ω9, C22:1ω9 and C24:1ω9; SEM, standard error of the mean; longissimus thoracis et lumborum, LTL; biceps femoris, BF; semimembranosus, SM; semitendinosus, ST; infraspinatus, IS; and supraspinatus, SS.

higher (p b 0.05) in LL from predominantly grazing male impala. The meat from male game species often has lower intramuscular fat percentages (Lawrie & Ledward, 2006) and therefore contains fewer triglycerides (Hoffman, Muller, Schutte, De, Calitz, & Crafford, 2005). Since essential PUFAs are mainly present in phospholipids (structural lipid components) (Bézard et al., 1994; Spector, 2006), the meat from male blesbok will have higher proportions of ω3 PUFA and ω6 PUFA, compared to the meat from female blesbok. Meat products with higher PUFA:SFA ratios are usually preferred since ω3 PUFA and ω6 PUFA (as opposed to SFAs) are more beneficial for human health (Lawrie & Ledward, 2006). The latter thus adds value to blesbok LTL (Table 6). A PUFA:SFA ratio of ≥ 0.45 and a ω6:ω3 of ≤ 4.0 are recommended in the UK (Warriss, 2000). The six blesbok muscles from this study area had PUFA:SFA ratios above the recommended value (Table 4), and in spring the ω6:ω3 for the muscles from both genders was below the recommended 4.0, however, in winter the ω6:ω3 of the forequarter muscles from male blesbok exceeded 4.0 (Table 3). Other researchers recommend that red meat have a PUFA:SFA ratio of ≥ 0.70 and a ω6:ω3 of ≤ 5.0 (Raes, De Smet, &

Demeyer, 2004; Scollan et al., 2006). With the latter recommendations, the PUFA:SFA ratios of all muscles from male animals, together with only the LTL from female animals were above ≥0.70 (Table 4), whereas all muscles had ω6:ω3 below 5.0 (Table 3). Blesbok meat from this study area can therefore be considered a healthy red meat alternative, due to the low overall intramuscular fat percentages and healthy fatty acid profiles. The small sample size (number of animals harvested per season) should, however, be taken into account. 5. Conclusions Muscle type and gender had the largest effects on the fatty acid profiles of the six blesbok muscles. Seasonal changes in the diet of the blesbok at this study area influenced the ALA percentages and therefore the total ω3 PUFA percentages and ω6:ω3. The muscles from female blesbok were more associated with higher palmitic acid percentages, while male blesbok muscles had higher proportions of total PUFAs and PUFA:SFA ratios. The meat from male blesbok muscles at this study area can therefore be considered healthier than those from females.

Table 6 Effect of muscle type on the fatty acid profile (g·100 g−1 of total fatty acids) of blesbok meat (means ± SEM). Fatty acids C16:0 C18:0 C18:2ω6c C18:3ω3 C20:5ω3 C22:5ω3 Total SFA Total PUFA ω3 PUFA a–d

Longissimus thoracis et lumborum c

19.01 23.25d 19.47a 5.40a 2.33a 2.76a 43.94c 40.97a 11.05a

± ± ± ± ± ± ± ± ±

0.555 0.617 1.114 0.396 0.155 0.213 1.112 2.308 0.708

Biceps femoris bc

19.10 24.81bc 17.02b 4.94b 2.28a 2.51ac 45.69c 37.71b 10.24b

± ± ± ± ± ± ± ± ±

0.489 0.756 1.173 0.416 0.174 0.249 1.245 2.580 0.790

Semimembranosus a

21.16 25.45b 15.52dc 4.75bc 2.13b 2.74ab 48.75b 35.24c 10.09b

± ± ± ± ± ± ± ± ±

0.458 0.893 1.001 0.365 0.138 0.217 1.352 2.119 0.696

Semitendinosus b

19.83 24.20dc 16.06bc 4.47c 2.24a 2.73ab 45.82c 36.37bc 9.97b

± ± ± ± ± ± ± ± ±

0.416 0.787 1.312 0.393 0.185 0.255 1.149 2.779 0.747

Infraspinatus a

20.84 27.06a 14.48d 4.10d 1.51c 2.31cb 50.09ab 31.38d 8.31c

± ± ± ± ± ± ± ± ±

0.427 0.654 1.149 0.357 0.120 0.193 0.958 2.227 0.615

Supraspinatus 20.98a 28.47a 14.42d 4.15d 1.48c 2.09c 51.83a 31.17d 8.11c

± ± ± ± ± ± ± ± ±

0.600 0.751 1.207 0.344 0.126 0.140 1.279 2.424 0.558

Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05); SFA, sum of saturated fatty acids = sum of C14:0, C15:0, C16:0, C18:0, C20:0, C21:0, C22:0 and C24:0; PUFA, polyunsaturated fatty acids = sum of C18:2ω6c, C18:3ω6, C18:3ω3, C20:2, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3 and C22:6ω3; ω3 PUFA, omega-3 polyunsaturated fatty acids = sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3; longissimus thoracis et lumborum, LTL; biceps femoris, BF; semimembranosus, SM; semitendinosus, ST; infraspinatus, IS; and supraspinatus, SS.

J. Neethling et al. / Meat Science 98 (2014) 599–606 Table 7 Effect of gender on the fatty acid profile (g·100 g−1 of total fatty acids) of blesbok meat (means ± SEM). Fatty acids

Male

C16:0 C16:1ω9 C18:2ω6c C20:5ω3 Total PUFA ω3 PUFA

19.05b 1.18a 19.62a 2.42a 43.03a 11.08a

Female ± ± ± ± ± ±

0.296 0.024 0.518 0.078 0.904 0.382

21.01a 0.95b 13.48b 1.67b 29.59b 8.50b

± ± ± ± ± ±

0.256 0.027 0.555 0.087 1.164 0.367

a,b

Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05); PUFA, polyunsaturated fatty acids = sum of C18:2ω6c, C18:3ω6, C18:3ω3, C20:2, C20:3ω6, C20:3ω3, C20:4ω6, C20:5ω3, C22:2ω6, C22:5ω3 and C22:6ω3; ω3 PUFA, omega-3 polyunsaturated fatty acids = sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3; SEM, standard error of the mean.

Table 8 Effect of season on the fatty acid profile (g·100 g−1 of total fatty acids) of blesbok meat (means ± SEM). Fatty acids

Winter 2010

Spring 2010

C18:3ω3 ω3 PUFA

3.53b ± 0.132 8.06b ± 0.325

5.74a ± 0.177 11.19a ± 0.377

a,b

Means within a variable with superscripts that do not have a common letter indicate significant differences (p b 0.05); ω3 PUFA, omega-3 polyunsaturated fatty acids = sum of C18:3ω3, C20:3ω3, C20:5ω3, C22:5ω3 and C22:6ω3; SEM, standard error of the mean.

Blesbok LTL, together with the BF and ST was generally considered more healthy for human consumption due to its higher total PUFA percentage and PUFA:SFA ratio, while the opposite was true for the SM and forequarter muscles. Although various significant gender and muscle type differences were found in the fatty acid profiles of these blesbok muscles, the small sample size (eight animals harvested per season) should be taken into account when considering the results from this study.

Acknowledgements The financial assistance of the National Research Foundation (NRF) (84633) towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the authors and are not necessarily to be attributed to the NRF. The help of the statistician, Prof M. Kidd for statistical analysis of data is appreciated. Special thanks to the Stellenbosch University Food Security Initiative (HOPE Project) for the additional financial assistance. Ms L. Uys (Department Animal Sciences) and Mr L. Mokwena from Stellenbosch University Central Analytical Facility are acknowledged for their contribution to the fatty acid analyses.

References Aidoo, K. E., & Haworth, R. J. P. (1995). Nutritional and chemical composition of farmed venison. Journal of Human Nutrition and Dietetics, 8, 441–446. Bézard, J., Blond, J. P., Bernard, A., & Clouet, P. (1994). The metabolism and availability of essential fatty acids in animal and human tissues. Reproduction Nutrition Development, 34, 539–568. Bothma, J. Du P., Van Rooyen, N., & Du Toit, J. G. (2010). Animals and their characteristics. In J. Du P. Bothma, & J. G. Du Toit (Eds.), Game ranch management (pp. 210–245) (5th ed.). Pretoria: Van Schaik Publishers. Cassens, R. G., & Cooper, C. C. (1971). Red and white muscle. Advances in Food Research, 19, 1–74. Chase, B.M., & Meadows, M. E. (2007). Late quaternary dynamics of southern Africa's winter rainfall zone. Earth-Science Reviews, 84, 103–138. Daley, C. A., Abbott, A., Doyle, P.S., Nader, G. A., & Larson, S. (2010). A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutrition Journal, 9, 1–12. Dewhurst, R. J., Scollan, N. D., Youell, S. J., Tweed, J. K. S., & Humphrey, M.O. (2001). Influence of species, cutting date and cutting interval on the fatty acid composition of grasses. Grass and Forage Science, 56, 68–74. Du Plessis, S. S. (1972). Ecology of blesbok with special reference to productivity. Wildlife Monographs, 30, 3–70.

605

Enser, M., Hallet, K., Hewitt, B., Fursey, G. A. J., Wood, J.D., & Harrington, G. (1998). Fatty acid content and composition of UK beef and lamb muscle in relation to production system and implication for human nutrition. Meat Science, 49, 329–341. Folch, J., Lees, M., & Sloane Stanley, G. H. (1957). A simple method for the isolation and purification of total fats from animal tissues. Journal of Biological Chemistry, 226, 497–509. Higgs, J.D. (2000). The changing nature of red meat: 20 years of improving nutritional quality. Trends in Food Science & Technology, 11, 85–95. Hocquette, J. F., Gondret, F., Baéza, E., Médale, F., Jurie, C., & Pethick, D. W. (2010). Intramuscular fat content in meat-producing animals: Development, genetic and nutritional control, and identification of putative markers. Animal, 4, 303–319. Hoffman, L. C., Kritzinger, B., & Ferreira, A. V. (2005). The effects of region and gender on the fatty acid, amino acid, mineral, myoglobin and collagen contents of impala (Aepyceros melampus) meat. Meat Science, 69, 551–558. Hoffman, L. C., Kroucamp, M., & Manley, M. (2007). Meat quality characteristics of springbok (Antidorcas marsupialis) 2: Chemical composition of springbok meat as influenced by age, gender and production region. Meat Science, 76, 762–767. Hoffman, L. C., Mostert, A.C., Kidd, M., & Laubscher, L. L. (2009). Meat quality of kudu (Tragelaphus strepsiceros) and impala (Aepyceros melampus): Carcass yield, physical quality and chemical composition of kudu and impala Longissimus dorsi muscle as affected by gender and age. Meat Science, 83, 788–795. Hoffman, L. C., Muller, M., Schutte, De, W., Calitz, F. J., & Crafford, K. (2005). Consumer expectations, perceptions and purchasing of South African game meat. South African Journal of Wildlife Research, 35, 33–42. Hoffman, L. C., Smit, K., & Muller, N. (2008). Chemical characteristics of blesbok (Damaliscus dorcas phillipsi) meat. Journal of Food Composition and Analysis, 21, 315–319. Hoffman, L. C., Van Schalkwyk, S., & Muller, N. M. (2008). Physical and chemical properties of male and female mountain reedbuck (Redunca fulvorufula) meat. South African Journal of Wildlife Research, 38, 11–16. Hoffman, L. C., Van Schalkwyk, S., & Muller, N. (2009). Effect of season and gender on the physical and chemical composition of black wildebeest (Connochaetus gnou) meat. South African Journal of Wildlife Research, 39, 170–174. Issanchou, S. (1996). Consumer expectations and perceptions of meat and meat product quality. Meat Science, 43, 5–19. Jansen van Rensburg, D.M. (2002). Venison as health food. In H. Ebedes, B. Reilly, W. Van Hoven, & B. Penzhorn (Eds.), Sustainable utilisation–conservation in practice. Proceedings of the 5th international wildlife ranching symposium. (pp. 196–198) (March 2002. Pretoria, South Africa). Katan, M. B., Zock, P. L., & Mensink, R. P. (1994). Effects of fats and fatty acids on blood lipids in humans: An overview. American Journal of Clinical Nutrition, 60, 1017S–1022S. Khan, N. A., Cone, J. W., Fievez, V., & Hendriks, W. H. (2012). Causes of variation in fatty acid content and composition in grass and maize silages. Animal Feed Science and Technology, 174, 36–45. Kohn, T. A., Kritzinger, B., Hoffman, L. C., & Myburgh, K. H. (2005). Characteristics of impala (Aepyceros melampus) skeletal muscles. Meat Science, 69, 277–282. Kruger, A.C. (2007). Climate of South Africa, precipitation, WS47. Pretoria, South Africa: South African Weather Service. Lawrie, R. A., & Ledward, D. A. (2006). Lawrie's meat science (7th ed.). Cambridge, England: Woodhead Publishing Limited. Lynch, C. D. (1971). A behavioural study of blesbok, Damaliscus dorcas phillipsi, with special reference to territoriality. Masters dissertation. University of Pretoria. McDonald, P., Edwards, R. A., Greenhalgh, J. F. D., & Morgan, C. A. (2002). Grass and forage crops. Animal nutrition (pp. 495–514) (6th ed.). Harlow: Pearson Prentice Hall. Mostert, R., & Hoffman, L. C. (2007). Effect of gender on the meat quality characteristics and chemical composition of kudu (Tragelaphus strepsiceros), an African antelope species. Food Chemistry, 104, 565–570. Neethling, J., Hoffman, L. C., & Britz, T. J. (2014). Impact of season on the chemical composition of male and female blesbok (Damaliscus pygargus phillipsi) muscles. Journal of the Science of Food and Agriculture, 94, 424–431. Purchas, R. W., Triumf, E. C., & Egelandsdal, B. (2010). Quality characteristics and composition of the longissimus muscle in the short-loin from male and female farmed red deer in New Zealand. Meat Science, 86, 505–510. Raes, K., De Smet, S., & Demeyer, D. (2004). Effect of dietary fatty acids on incorporation of long chain polyunsaturated fatty acids and conjugated linoleic acid in lamb, beef and pork meat: A review. Animal Feed Science and Technology, 113, 199–221. Ramanzin, M., Amici, A., Casoli, C., Esposito, L., Lupi, P., Marsico, G., Mattiello, S., Olivieri, O., Ponzetta, M. P., Russo, C., & Marinucci, M. T. (2010). Meat from wild ungulates: Ensuring quality and hygiene of an increasing resource. Italian Journal of Animal Science, 9, 319–366. Rebelo, A. G., Boucher, C., Helme, N., Mucina, L., & Rutherford, M. C. (2006). Fynbos biome. In L. Mucina, & M. C. Rutherford (Eds.), The vegetation of South Africa, Lesotho and Swaziland (pp. 55–208). South Africa: South African National Biodiversity Institute. Robert, C., Audigié, F., Valette, J. P., Pourcelot, P., & Denoix, J. -M. (2001). Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse. Equine Veterinary Journal, 33, 154–159. Rutherford, M. C., Mucina, L., & Powrie, L. W. (2006). Biomes and bioregions of southern Africa. In L. Mucina, & M. C. Rutherford (Eds.), The vegetation of South Africa, Lesotho and Swaziland (pp. 31–51). South Africa: South African National Biodiversity Institute. Schönfeldt, H. C., & Gibson, N. (2008). Changes in the nutrient quality of meat in an obesity context. Meat Science, 80(1), 20–27. Scollan, N., Hocquette, J. F., Nuernberg, K., Dannenberger, D., Richardson, I., & Moloney, A. (2006). Innovations in beef production systems that enhance the nutritional and health value of beef lipids and their relationship with meat quality. Meat Science, 74, 17–33. Skinner, J.D., & Chimimba, C. T. (2005). Order Ruminantia. The mammals of the southern African subregion (pp. 616–714). Cambridge: Cambridge University Press.

606

J. Neethling et al. / Meat Science 98 (2014) 599–606

Spector, A. A. (2006). Essential fatty acids. Biochemical, physiological, molecular aspects of human nutritional (pp. 518–540) (2nd ed ). Saunders: Elservier. STATISTICA (2011). STATISTICA data analysis software system, version 10.0.228.2. Tulsa, United States of America: StatSoft Inc. Taylor, R. G. (2004). Muscle fibre types and meat quality. In W. K. Jensen, C. Devine, & M. Dikeman (Eds.), Encyclopedia of meat sciences, Vol. 2. (pp. 876–882). Oxford: Elsevier Academic Press. Van Schalkwyk, D. L., & Hoffman, L. C. (2010). Overview of the Namibian game meat industry. Guidelines for the harvesting of game for meat export (pp. 1–10). Namibia: AgriPublishers (http://scholar.sun.ac.za/handle/10019.1/79639).

Warriss, P. D. (2000). Meat science: An introductory text. Wallingford: CABI Publishing. Wood, D., & Enser, M. (1997). Factors influencing fatty acids in meat and the role of antioxidants in improving meat quality. British Journal of Nutrition, 78, S49–S60. Wood, J. D., Richardson, R. I., Nute, G. R., Fisher, A. V., Campo, M. M., Kasapidou, E., Sheard, P. R., & Enser, M. (2003). Effects of fatty acids on meat quality: A review. Meat Science, 66, 21–32.