Browsing by Author "Muchenje, V."
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Item Animal Breeding: AGA 322, Degree examinations November 2018(University of Fort Hare, 2018-11) Mpayipheli, M.; Muchenje, V.Item The effect of feed restriction duration on growth performance, physico-chemical characteristics and fatty acid composition of meat from broilers.(University of Fort Hare, 2014) Gobane, Ziphozihle; Muchenje, V.The main objective of the study was to determine the effect of feed restriction duration on growth performance, physico-chemical characteristics (colour, ultimate pH, tenderness and cooking loss) and fatty acid composition of meat from broilers. A total of 144 day-old broiler chicks were reared in a deep litter system until slaughter at 42 days. All the chicks were managed in one brooding house for the first 21days. On day 22, the chicks were randomly allocated to three treatments; the control (T1), one week of feed restriction (T2), and two weeks of feed restriction (T3). Three broiler houses with uniform conditions were sub-divided into three compartments. The birds were randomly allocated to each of the nine compartments. Each treatment was replicated three times with 16 birds per compartment being fed as a group and each bird was regarded as the experimental units. The average daily gain (ADG), average daily feed intake (ADFI) and the feed conversion ratio (FCR) were computed for each chick each week. Chickens were all slaughtered at 42 days of age and the slaughter weight, carcass weight, and internal organs weights were recorded. Physico-chemical qualities of chicken breast meat such as colour (L*-lightness, b*-yellowness, a* redness, saturation index and hue angle) and meat ultimate pH (pHu) measurements were taken over a 10 days shelf-life period. Breast muscle was also sampled for cooking loss, tenderness and fatty acid profiles. There were treatment effects on the growth performance of broiler chickens. There was no significant effect (P > 0.05) on the relative weights of the chicken heart, liver, gizzard, feet and heads among the treatment groups except for intestine weight. Treatment 1 had higher live weight than treatment 2 and 3. There was significant effect (P < 0.05) on the cooking loss breast muscle, with treatment 1 having highest values. However, feed restriction had no effect (P > 0.05) on the WBSF of breast muscle, although it was highest in T 3. Feed restriction had no effect (P > 0.05) on hue angle, significant difference (P < 0.05) was observed on meat pHu, L *, a*, b* and saturation index after 24 hours of storage. Birds that were exposed to two weeks of feed restriction had the highest ultimate pH (5.99) followed by one week restriction (6.01) and the broilers which were fed ad libitum (5.89). The pHu values in all the treatments were constant from day 1 to day 6 and then T 2 peaked up at day (6.16) before declining at day 8 (5.91). The L* values in all treatments were constant from day 1 to day 7 and then at day 8, treatment 2 reached its peak L* (58.49) and then declined on day 9 (44.38) with T 3 having similar values. The b* values started to decrease from day 3 to day 6 then peaked up again at day 7 except for T 1. There was no significant treatment effects (P > 0.05) on the SI and Hue angle on breast muscle. There was no treatment effect on the major fatty acids of breast muscle. It was concluded that a one week feed restriction had similar effects on growth performance and meat quality of broiler chickens as non-restriction broilers. The meat quality of the broiler muscle was within the normal range, feed restriction did not affect meat quality of broiler meat. Feed restriction had a minimal effect on physicochemical shelf-life indicators of broiler chickens during storage over 10 days. The observation from this study showed that all the treatment had a minimal effect on the fatty acids of the broiler chicken.Item The effect of grain and soya bean-based diets on chicken production, some egg quality traits, and the potential for allergen carryover to eggs and meat.(University of Fort Hare, 2015) Dokora, Adia-En-Michelle; Muchenje, V.This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15% whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15% whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15% whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15% whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth. Egg production was also maintained without the possibility of soy and gluten allergens being carried over from the feed into the eggs and meat.Item Effect of Tenebrio molitor larvae as a protein source on growth performance, carcass yield and meat quality of broiler chickens.(University of Fort Hare, 2016) Mngqi, Sinethemba Census; Muchenje, V.This study was conducted to assess the effect of including Tenebrio molitor larvae (T. molitor L) as a protein source in different diets on broiler performance, carcass characteristics and meat quality. A total of 144 day-old Cobb-500 chicks were randomly allocated into three treatment groups, each was allocated 16 birds and reared in 9 identical pens. Experimental diets used were as follows: T1 Control (no T. molitor L inclusion); T2 and T3 contained levels of T. molitor L at 5% and 10% of dry matter (DM) intake, respectively. Body weights (BW), average daily gain (ADG), feed intake (FI), and Feed conversion ratio (FCR) were measured for the 1st experimental chapter. For the second experimental chapter; live weights (LW) of broilers were recorded before slaughter and thereafter carcass weights (CW), meat yield (weights of breast, thigh, drumstick and wing) were recorded. The dressing percentage (DP %) was also calculated. Breast muscles were sampled for meat pH and colour measurements. The LW of birds from T1 (0% T. molitor L) were significantly different (P<0.05) from both T2 (5% T. molitor L) and T3 (10% T. molitor L) which were similar to each other, with T2 exhibiting the highest live weights (2166g) and the control treatment exhibiting the lowest live weights (2018.3g). In CW, T1 was significantly different (P<0.05) from T2 while it was similar (P>0.05) to T3. The dressing % of T1 was significantly different (P<0.05) from T2 and T3 which were similar to each other, with T2 having the highest dressing percentage (78, 2%) and T1 having the lowest DP% (66%). The breasts in T2 were significantly higher and different (P<0.05) from both T1 and T3 which were similar to each other. The drumsticks in T3 were significantly different (P<0.05) from T1 while they were similar to T2 with values with T2 having highest values. After 45 minutes of slaughter, a significant difference (P<0.05) was observed in L⃰ among all treatments. In redness (a⃰), T3 was significantly different from T1 but was similar to T2 and all treatments in this study exhibited a darker red meat, with T3 muscles exhibiting darker red colour than the other treatments. Similar results were observed in yellowness (b⃰), where the breast muscles from T3 were more yellow than the other treatments. After 24 hours of slaughter, T2 L⃰ values were significantly different (P<0.05) from both T1 and T3 which were similar to each other. It was also found that the broiler chickens given diet with no T. molitor L inclusion (T1) had lower values of BW, FI, ADG and FCR throughout the experiment than those that were in T2 and T3 with 5% and 10 % T. molitor L inclusion levels, respectively. However, it was also found that although broilers with 5% T. molitor L inclusion (T2) in their diet had high ABW and ADG than the broilers with 10% T. molitor L inclusion (T3), the T3 birds compared favourably to T2 birds as they required low feed intake to reach the same slaughter weight due to high FCR. It was, therefore, concluded that T. molitor L meal can be incorporated into the diets of broilers to produce heavy birds either at 5 or 10%. However, although 5% T. molitor L inclusion yields heavier carcasses, the 10% T. molitor L inclusion compared favourably to 5% inclusion since it required low feed intake to reach the same slaughter weights and there were slight differences on meat quality attributes between the two treatments.Thus T. molitor L at 10% inclusion levels was the best inclusion level to enhance broiler growth performance, carcass yield, meat yield and meat quality.Item Farm to abattoir conditions and their subsequent effects on behavioural and physiological changes and the quality of beef from extensively-reared Nguni and non-descript steers.(University of Fort Hare, 2016) Njisane, Yonela, Z; Muchenje, V.The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37%); though it was reduced (26.9±2.64%) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04%) and standing (20.8±4.63%) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40%) and not kicking than the ND steers that were more vocal (20–60%) and kicking (> 5%). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2%) pre-slaughter than those in TG2 (23.9%). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5%), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24%). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear. In addition, the genotype differenceItem Fatty acid composition, colour stability and lipid oxidation of mince produced from fresh and frozen/thawed fallow deer meat.(University of Fort Hare, 2016) Chido, Chakanya; Muchenje, V.The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4% (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life, the proximate composition of the meat remains unchanged.Item Glycolytic potential and meat quality from Dorper and Merino sheep.(University of Fort Hare, 2015) Stempa, Thuthuzelwa; Muchenje, V.The objective of the study was to determine glycolytic potential and meat quality from Dorper and Merino sheep of both sexes slaughtered at a commercial abattoir. Dorper (n=52) and Merino (n= 48) breeds aged eight years, consisting of 50 intact rams and 50 non-pregnant ewes were used in the study. The sheep used in the study were reared, transported and lairised under identical conditions. Blood samples were collected at exsanguination for the measurement of glucose, lactate and cortisol levels. Samples were also collected from the Muscularis longmissius thoracis et lumborum (LTL) for the measurement glycogen, lactate levels, pH decline and colour. Correlations amongst blood stress indicators, muscle metabolites and meat quality attributes were also determined. Sex and breed had no effect on muscle glycolytic potential, glycogen and lactate levels from Dorper and Merino sheep of both sexes at the abattoir. Although sex and breed had an effect on pre-slaughter stress indicators (lactate and cortisol) collected at exsanguination. Ewes had higher levels of blood lactate (7.4 3 ± 0.49 mmol/L) and cortisol (293.92 ± 14.32 nmol/L) than the rams which had (5.19 ± 0.49 mmol/L) and (179.50 ± 14.32 nmol/L) lactate and cortisol levels, respectively. Furthermore, higher levels of lactate were observed in Dorper (7.54 ± 0.42 mmol/L) compared to the Merino sheep (4.97 ± 0.49 mmol/L). Meat pH decline and colour were also significantly affected by sex and breed. Ewes had higher levels of at pH45 minutes post slaughter iii (7.05 ± 0.04), pH3 hours (6.45 ± 0.04) , pH24 hours (6.00 ± 0.03), a* (14.31 ± 0.33) , b* (8.84 ± 0.29), H* (31.47 ± 0.73) and C* (16.75 ± 0.24) compared to the rams which had pH45 minutes (6.44 ± 0.04), pH3 hours (6.12 ± 0.04), pH24 hours (5.88 ± 0.03), a* (12.25 ± 0.33), b* (7.00 ± 0.29), H* (29.36 ± 0.73) and C* (14.15 ± 0.42) values. Moreover, Merino sheep had higher levels of L* (38.17 ± 0.48) and H* (31.59 ± 0.74) compared to the Dorper which had (36.39 ± 0.46) and (29.33 ± 0.71) L* and H* values, respectively. Blood cortisol was also positively correlated (P < 0.05) to glucose (r = 0.27), lactate (r = 0.37) but was negatively correlated (P < 0.001) to meat lightness (r = -0.44). Furthermore, blood cortisol was positively correlated (P < 0.001) to pH45 (r = 0.34), pH24 (r =0.22), meat yellowness (r = 0.24) and chroma (r = 0.37), but was negatively correlated to meat lightness (r = -0.47). Glycolytic potential was positively correlated (P < 0.001) to muscle glycogen levels (r = 0.66) and muscle lactate (r = 0.71).Item Meat condemnation in slaughtered bovine species in the Eastern Cape Province, South Africa.(University of Fort Hare, 2014) Jaja, Ishmael Festus; Muchenje, V.; Green, E.A study was conducted in three abattoirs represented by the acronym ANA, QTA and EBA, to determine the causes of meat condemnation and to ascertain monetary losses associated with such condemnation. Ante-mortem and active abattoir surveys were conducted on 229, 458 and 687 cattle from the three abattoirs respectively and abattoir slaughter records (n=51, 302) was obtained from 2010 to 2012. The abattoir records showed that the liver was the most frequently condemned (56.9%), followed by the lung (24.1%), then the heart (7.4%), kidney (6.9%), spleen (4.0%), tongue (0.4%) and carcass (0.3%). An assessment of the abattoir secondary data revealed that the major cause of condemnation of the liver at ANA, QTA and EBA was fasciolosis (5.59, 4.48, 2.68), spleen (abscess, 0.35, 0.94, 0.17) kidney (inflammation, 0.94, 1.01, 1.18), heart (inflammation, 0.9, 1.85, 0.75), tongue (abscess, 0.08, 0.03, 0.05) and lungs (emphysema, 1.12, 1.14, 1.16). Disease/conditions recorded during ante-mortem inspection of animals at the lairage were diarrhea, lameness, emaciation, blindness, orchitis, mastitis, skin conditions, and respiratory symptoms corresponding to 8, 1, 13, 2, 3, 6, 9, and 11 percent, respectively. The percentage of condemned organs was higher during the active abattoir meat inspection than in the previous records from the abattoir. Additional losses of tongue due to gunshot injury and the heart due to cysticercosis were recorded. Prevalence of fasciolosis was calculated and seasonal occurrence was determined based on monthly assortment. From the retrospective data, the prevalence of fasciolsis was 2.9 percent (n = 78728) while the annual (2011, 2012, 2013) prevalence of Fasciola infection for AB1 was (3.2, 2.2 and 2.0%), AB2 (6.4, 4.6 and 3.5%) and AB3 (14.4, 6.9 and 9.5%). Higher prevalence was obtain in summer (AB1 = 10.4%, AB2 = 12.8% and AB3 = 10.9%) and autumn (AB1 = 11.2%, AB2 = 10.8% and AB3 = 8.6%) than in winter (AB1 = 9.8%, AB2 = 6.5% and AB3 = 5.9%) and spring (AB1 = 8.2%, AB2 = 7.8% and AB3 = 5.9%). Monetary loss associated with carcass/offal condemnations in the three abattoirs from 2010 to 2012 was 630, 456 South African Rand (ZAR) or 59, 244 United States Dollars (USD), while the summation of losses due to condemnation during the 6 month active meat inspection revealed a higher loss of ZAR 111, 337.5 (10, 383.8 USD) . Monetary losses associated with carcass weight loss, whole and partial liver condemnation due to infection with Fasciola was calculated as ZAR 917, 921.5 (83, 447 USD), ZAR 31, 661.5 (2, 878 USD) and ZAR 19, 112.3 (1, 737 USD) respectively. In conclusion, organs and carcasses were condemned for several disease and non-disease factors and this led to significant financial loss.Item Meat Science: AGA 421, Supplementary Examinations January 2019(University of Fort Hare, 2019-01) Mpayipheli, M.; Muchenje, V.; Hugo, A.