Effect of Mucuna pruriens based-diets on fatty acids composition and sensory attributes of meat from broiler chickens
- Authors: Makhamba, Nasiphi
- Date: 2020-11
- Subjects: Fatty acids , Broilers (Chickens)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20771 , vital:46554
- Description: The current study was conducted to determine the effect of feeding different inclusion levels of processed Mucuna pruriens on fatty acid composition and sensory attributes of broiler chickens. 120 Cob500 broilers were used in the experiment. The experiment was divided into 4 treatment (0, 10, 15 and 20 percent of Mucuna pruriens) groups, each treatment with 6 replicates (5 birds per replicate) in a completely randomized design. The first treatment (0 percent) was used as control against the three different levels of Mucuna pruriens. The birds were reared in a deep litter system until they reached slaughter weight of 2kg. At day 42 a total of 80 birds were slaughtered and breast muscles were sampled for the evaluation of sensory attributes and fatty acid composition. For sensory evaluation meat samples were prepared and boiled at 80°C until the internal temperature reached 82°C, 40 consumers were used to assess the meat samples and give scores according to 9-point hedonic scale. The fatty acid content was determined and recorded using the gas chromatography. Total saturated fatty acid (SFA), total monounsaturated fatty acid (MUFA), and total polyunsaturated fatty acid (PUFA) of the breast meat were not affected by diets. Omega-6 and omega-3 fatty acid were also not influenced by treatment diets. However, breast muscle from broilers fed 20 percent Mucuna pruriens seed meal inclusion had lower Myristic acid. The sensory attributes; aroma, colour, flavour, juiciness, tenderness and acceptability were assessed, dietary treatments affected the juiciness, tenderness and acceptability of meat, the treatments showed no significant difference on colour, aroma and flavour. Different age groups accepted the meat differently, the respondents that were between 18 and 22 years old gave the highest scores to the acceptability of meat than the other age groups, and different age groups also gave different scores in the aroma of meat. Females and males accepted the meat differently, the female respondents gave higher scores on the flavour of meat than males. Different inclusion levels of Mucuna pruriens positively affected fatty acid composition and sensory attributes of broiler chickens without causing any detrimental effects. , Thesis (MSc) (Animal Science) -- University of Fort Hare, 2021
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- Date Issued: 2020-11
Effects of dietary inclusion of Moringa oleifera leaf meal on growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork
- Authors: Nduku, Xola Pauline
- Date: 2014
- Subjects: Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11836 , http://hdl.handle.net/10353/d1021281 , Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Description: The objective of the study was to determine growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork from pigs fed one of three dietary treatments, eac containing 0%, 2.5% or 5% (T1, T2 and T3, respectively) Moringa oleifera leaf meal (MOLM). Dietary treatments were formulated to be isonitrogenous and isoenergetic for weaner (6 – 8 weeks) and grower (9 – 13 weeks) phases. Twelve Large White (LW) and 12 Kolbroek (KB) male pigs at 6 weeks of age, initially weighing an average 10 kg, were randomly allocated to one of the dietary treatments, each with four replicates, in individual pens. Feed and water were offered ad libitum. The Longissimus thoracis et lumborum (LTL) muscle of each carcass (n = 24) was sampled for meat quality and fatty acid analyses. Breed differences in measured parameters were observed. In pigs receiving 5% MOLM, the LW had significantly the highest ADFI (P<0.05) than KB pigs. In pigs receiving 2.5% and 5% MOLM, backfat thickness was significantly highest (P<0.05) compared to those receiving 0% MOML. Dietary inclusion of MOLM had no significant effects (P>0.05) on the physico-chemical quality of pork from LW pigs; although it significantly (P<0.05) increased a* and reduced WBSF values in pork from KB pigs. Pork from LW pigs receiving 5% MOLM had significantly increased (P<0.05) n-3 content of the subcutaneous tissue of LW pigs compared to KB, and also when compread to other treatment groups. In both breeds, the composition of PUFA: SFA and n-6: n-3 in the subcutaneous adipose tissue was significantly (P<0.05) lower in T2 and T3 than in T1. The n-3 levels for pork muscle from LW pigs receiving 2.5% and 5% MOLM, and from KB pigs receiving 5% MOLM, were significantly (P<0.05) lower. Inclusions of MOLM significantly (P<0.05) reduced the n-6: n-3 fatty acids in pork from both LW pigs and KB pigs. Consumer scores on sensory attributes (aroma intensity, initial impression of juiciness, first bite, sustained impression of juiciness, muscle fibre and overall tenderness and overall flavor intensity) significantly (P<0.05) increased as the level of MOLM inclusion in the diet increased; and higher scores were observed in fried meat than in boiled for most sensory attributes. It may be concluded that inclusion of MOLM in pig diets up to 5% improved the ADFI, a*, tenderness of pork without adversely affecting the FCR and other physico-chemical quality attributes; and resulted in desired increase in levels of n-3 and reduced the n-6: n-3 fatty acid ratio.
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- Date Issued: 2014
Temporal variability in the fatty acid composition of suspension-feeders and grazers on a South African rocky shore
- Authors: Ndhlovu, Rachel Tintswalo
- Date: 2014
- Subjects: Lipids , Suspension feeders -- South Africa , Intertidal organisms -- South Africa , Marine invertebrates -- South Africa , Marine invertebrates -- Food -- South Africa , Marine invertebrates -- Life cycles -- South Africa , Marine invertebrates -- Reproduction , Benthos -- South Africa , Intertidal ecology -- South Africa , Fatty acids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5949 , http://hdl.handle.net/10962/d1020879
- Description: Numerous ecological studies have used lipids to determine trophic pathways in aquatic systems, as fatty acid profiles provide time-integrated information on an organism’s assimilated diet. Many of these studies have, however, been based on sample collections with a limited temporal scale. The trophic ecology of pelagic systems has been studied intensively using fatty acid analyses, but very little work has been directed toward benthic communities, with the intertidal being especially neglected. The investigation of trophic pathways within rocky shore communities will help us to better understand system responses to environmental changes. The determination of long term temporal variation of the food web within a community could reveal the type, magnitude, duration and frequency of highly seasonal productivity. Changes in fatty acid profiles through time in primary consumers of intertidal rocky shores are poorly understood, but represent an important step towards a more comprehensive understanding of rocky shore food webs, compared with those derived from snapshot or short-term studies. The aim of this thesis was to clarify the temporal variability in the diets of rocky shore intertidal suspension-feeders (the brown mussels Perna perna and the Cape reef worm, Gunnarea gaimardi) and grazers (the Cape sea urchin Parencinus angulosus and the Goat-eye limpet, Cymbulus oculus) on the south east coast of South Africa using fatty acid profiles, and to investigate the effects of life style (e.g. feeding mode) and life cycle on temporal variations in tissue fatty acid profiles. I had three hypotheses: firstly, that suspension-feeders experience high levels of variability in their diets through time because water quality has the potential to change quickly and drastically, whereas grazers experience less variability in their diets over time since their food sources are more constant. Secondly, the reproductive cycles of the suspension-feeder P. perna and the grazer P. angulosus affect the fatty acid composition of their gonads, with temporal variations in lipid composition reflecting changes in reproduction investment. Thirdly, the total amount of energetic reserves available for reproduction are different for each gender (females allocate more energy to egg production than males allocate to gamete production). To address these aims, fatty acid profiles of suspension-feeders and grazers were investigated over a period of twelve months (from July 2010 to June 2011) at a single site on the south east coast of South Africa. The results showed high variability in the fatty acid composition of both the suspension-feeders strongly related with changes in their food source (suspended particulate material). Furthermore, similar temporal changes in fatty acid profiles of the two suspension-feeders were observed over time, reflecting their common diet and life style. There were some inter-specific differences in the suspension-feeders, likely originating from differences in their particle capturing mechanisms. Grazers showed less variability through time compared with the suspension-feeders, with the limpets being more consistent than the sea urchins. The temporal variability in the sea urchin diets may have resulted from the highly diverse and heterogeneous food sources available to them, whereas limpets may be more selective and have a limited range of diet items. Differences between the two grazer species may have arose from differences in their feeding strategies and intertidal zonation. The fatty acid compositions of gonad tissues in both P. perna and P. angulosus showed temporal variability strongly related to reproductive cycle. Differences in the fatty acid values between females and males were apparent, with females richer in total and polyunsaturated fatty acids than males. Spawning and gametogenesis influenced the variability of fatty acids through time in both species, suggesting the importance of considering the reproductive cycle when studying lipids in rocky shore species. Little evidence of lipid transfer between muscles and gonads was seen, suggesting the importance of direct lipid storage into the reproductive tissues. The influence of diet and life history of intertidal consumers on the temporal variability of their fatty acid compositions is important to understand, as it provides us with a better understanding of the functioning of rocky shore systems. There is an enormous potential for future research in this field of study.
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- Date Issued: 2014
Trophic relationships of hake (Merluccius capensis Castelnau, 1851 and M. paradoxus Franca 1960) from the Northern Benguela current ecosystem (Namibia) : inferences from stable isotopes and fatty acids
- Authors: Iitembu, Johannes Angala
- Date: 2014
- Subjects: Hake -- Benguela Current , Merlucciidae -- Benguela Current , Multitrophic interactions (Ecology) , Food chains (Ecology) , Biotic communities -- Benguela Current , Merlucciidae -- Food , Fishery management -- Namibia , Stable isotopes , Fatty acids
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5944 , http://hdl.handle.net/10962/d1020296
- Description: Two species of hake (Merluccius capensis and Merluccius paradoxus) account for most of Namibia’s fisheries catch, and they are important secondary consumers in the Benguela Current ecosystem. Inferences on their trophic relationships have been based mainly on stomach content analyses. However, such data are limited temporally because they represent only snapshots of recent feeding, and are quantitatively biased because of variation in the digestion rates of different prey. The principal aim of the thesis was to understand the trophic relationships of two hake species relative to each other, their known prey and top predators (demersal sharks) in the northern Benguela Current ecosystem (Namibia), using time-integrating trophic biomarkers. By using stable isotope (carbon and nitrogen) and fatty acid signatures of their muscle tissues, my overall objectives were to produce new knowledge about 1) hake ontogenic trophic relationships, 2) the contributions of different prey to hake diets, 3) hake dietary differences, and 4) some aspects of hake’s trophic relationships with demersal sharks. Tissues of hake (n=358), their potential prey (n=455), and demersal sharks (n=42) were collected between 2008 and 2012 during demersal bottom trawl surveys off Namibia, for stable isotope and fatty acid analyses. And more...
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- Date Issued: 2014
Milk production and calf performance in Nguni and crossbred cattle raised on communal rangelands of the Eastern Cape province of South Africa
- Authors: Mapekula, Monde
- Date: 2009
- Subjects: Nguni cattle , Communal rangelands -- South Africa -- Eastern Cape , Dairy processing -- South Africa -- Eastern Cape , Milk yield -- South Africa -- Eastern Cape , Amino acids -- South Africa -- Eastern Cape , Fatty acids
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11813 , http://hdl.handle.net/10353/247 , Nguni cattle , Communal rangelands -- South Africa -- Eastern Cape , Dairy processing -- South Africa -- Eastern Cape , Milk yield -- South Africa -- Eastern Cape , Amino acids -- South Africa -- Eastern Cape , Fatty acids
- Description: Information on milk production could be useful in designing strategies that would help to improve milk production in communal farming systems. This study was conducted to determine milk production and calf performance of Nguni and crossbreds under smallholder cattle production conditions. Four trials were conducted in the study. The objective of the first trial was to determine farmer perceptions on milk production and calf rearing in smallholder areas. Data were obtained from 218 smallholder farmers, using a structured questionnaire. Smallholder farmer sector is constituted by small scale commercial farmers and communal farmers. Small-scale commercial farmers in South Africa obtained farms from the government through land claims or they bought the farms. Their farming background is a communal type. Communal farmers are farmers that are sharing the same grazing land and animals are managed according to the experience of the owner. The findings in this study indicated that there were numerous constraints to milk production in smallholder areas. These included lack of technical expertise and poor veterinary support services. The farmers also indicated that calf performance was low. The second trial was conducted to determine if there were differences in calf performance, gastrointestinal parasites and nutritionally-related blood metabolites between Nguni and crossbred calves. Body weights and faecal samples were collected monthly until weaning at six months. The levels of total protein, albumin, globulins, non-esterified fatty acids (NEFA), glucose, cholesterol and minerals were determined monthly. Nguni calves had higher birth weights than crossbreds (P<0.05). Average daily gain and weaning weights of Nguni calves were greater than crossbred calves (P<0.05. Nguni calves had lower total protein at early age after birth (P<0.05). However, at weaning Nguni calves had higher total protein than crossbreds (P<0.05). Nguni calves had higher levels of glucose and NEFA concentrations than crossbred calves (P<0.05). In the third trial, milk utilisation patterns in smallholder areas of the Eastern Cape were assessed. Cattle owners (n = 130) were randomly selected in three different regions to determine milk consumption patterns, milk sales, prices and factors influencing these activities. The information was gathered using milk recording sheets, which were administered in February (early lactation) and June (late lactation) in 2009. Milk consumption per household was similar among the three districts (P>0.05). Milk was utilised as both fresh and sour. Fresh milk was utilised with tea/coffee and porridge. Excess fresh milk was utilised to feed pets (mostly cats and puppies). The puppies were fed on mostly whey, and, at times, on fresh milk. Sour milk was utilised to prepare of umvubo (a mixture of sour milk and scrambled porridge (umphokoqo) or a mixture of sour milk and bread). In some cases, excess milk was given to neighbours as a form of social investment and fame. The quality of milk from Nguni and crossbred cows was compared in the fourth trial. Milk samples were evaluated for quality in early (February), mid (April) and late (June) lactation in 2009. The essential amino acids, non-essential amino acids and fatty acids were determined. Nguni milk had higher amino acids and fatty acids concentration than crossbreds (P<0.05). Nguni milk had higher arginine levels in the early and mid lactation periods compared to crossbred cows (P<0.05). Nguni milk had higher methionine and threonine levels than crossbred cows (P<0.05). Methionine levels in Nguni were 0.15, 0.19 and 0.18 in early, mid and late lactation while crossbred had 0.05, 0.05 and 0.06 (g/100ml), respectively. There were significant interactions between lactation stage and genotype for lysine levels with Nguni milk having higher (P<0.05) lysine levels in the mid and late lactation periods. Nguni cows had higher tyrosine, glycine and proline levels than crossbred cows (P<0.05). In the early lactation, Nguni cows had higher serine levels than crossbred cows (P<0.05). In mid lactation crossbred cows had higher serine levels than Nguni cows (P<0.05). There were significant differences between genotypes on fatty acid composition. Nguni milk had higher C12:0 levels than crossbreds (P<0.05). However, milk from crossbred cows had higher C14:0 levels than that for Nguni cows (P<0.05) and also had higher levels of C16:0 and C18:0 fatty acids compared to Nguni cows. Crossbred milk had higher levels of C18n1n9t in early lactation period than Nguni and decreased as the stage of lactation progressed (P<0.05). In the early lactation, the levels of C18n1nC in Nguni milk were higher (P<0.05) than in late lactation. In the mid and late lactation, crossbred cows milk had higher C18n1nC levels than in early lactation (P<0.05). Lactation stage and genotype affected saturated fatty, monounsaturated fatty acids, cis-fatty acids and omega 3 (n-3) to omega 6 (n-6). In general, Nguni milk had higher mineral composition than crossbred milk (P<0.05). In conclusion, Nguni calves performed better than crossbred calves under communal rangelands. There is a need for crossing Nguni cows with dairy breeds in commercial dairying by smalhoder farmers as a strategy for improving both milk quality and quantity.
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- Date Issued: 2009
Essential fatty acids and ascorbic acid- interactions and effects on melanoma growth
- Authors: Gardiner, Neil Stockenstrom
- Date: 1990
- Subjects: Fatty acids , Melanoma , Mice -- Diseases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4549 , http://hdl.handle.net/10962/d1018230
- Description: The present study was carried out to determine the effects and possible mechanisms of action of the essential fatty acids (EFAs) (linoleic acid (LA), gamma-linolenic acid (GLA) and arachidonic acid (AA)) and ascorbic acid (Asc) on BL6 murine melanoma growth in cell culture and in mice. Interactions between the nutrients in influencing melanoma growth as well as possible mechanisms of the interactions were also examined in the above systems. Cell culture studies revealed that all three EFAs (0-SOμg/ml) and Asc (0-200μg/ml) significantly inhibited melanoma growth at the concentrations used. The EF As were also found to significantly inhibit growth, although to a lesser extent than BL6 cells, of monkey kidney (LLCMK) cells which were used as a non-malignant control cell line. Asc in contrast was found not to inhibit growth of these cells. Supplementation of Asc (lOO)μg/ml) to EFA containing (0-50μg/ml) medium was found to significantly increase inhibition of cell growth in both cell lines, and in the BL6 cells in particular, after taking into account the growth inhibitory effects of Asc in the absence of EFAs. The mechanism of cell growth inhibition by the EF As appeared to involve lipid peroxidation but not enhanced prostaglandin (PG) or leukotriene (LT) synthesis. While Asc was found to increase both lipid peroxidation and PG synthesis in the cells, these mechanisms and enhanced LT synthesis did not appear to have played a role in the inhibition of cell growth by Asc or in the growth inhibitory interaction between Asc and the EF As. In vivo studies revealed that diets containing essential or polyunsaturated fatty acids (EFAs/PUFAs) in the form of vegetable oils, and in particular GLA in the form of evening primrose oil, significantly promoted melanoma growth in mice when compared with an EFA/PUFA free diet containing predominantly saturated fats (SF). Supplementary dietary Asc in contrast was found to significantly inhibit melanoma growth in mice fed EFA/PUFA, and in particular GLA, containing diets but not in mice fed SF cont~g diets. This result appears to indicate the occurrence of an interaction between the two nutrients. Ul The mechanism of tumour promotion by the EP As/PUP As did not appear to have involved enhanced PG or LT synthesis or lipid peroxidation. Since dietary EPA/PUPA manipulation was found to significantly alter the EPA content of tissues, including the melanomas, the mechanism of tumour promotion may have involved changes in the EPA composition of the tumour cells. While supplementary Asc was found to significantly increase the Asc content of certain tissues, including the melanomas, which may have played a role in tumour growth inhibition by Asc, it was found not to affect the EPA content of tissues. Enhanced PG or LT synthesis and lipid perox:idation did not appear to have been involved in the tumour growth inhibitory interaction between Asc and the EP As/PUP As. THe activity of the enzyme delta-6-desaturase, a key enzyme in EF A metabolism which catalyses the desaturation of LA to GLA, and the influence of Asc on activity of the enzyme were also examined. The cultured cells, and BL6 cells in particular, were found to contain significant activity of the enzyme. Whereas murine liver microsomal fractions were found to contain delta-6-desaturase activity, microsomes from melanomas grown in mice were found to lack activity of the enzyme. The significant tumour promoting effects of the GLA containing EPO diet may have been the result of the lack of delta-6-desaturase activity in tumour cells grown in mice. Asc was found to stimulate activity of the enzyme in cultured BL6 cells but not in LLCM.K cells, while dietary Asc and EF A/PUP A manipulation did not influence activity of the enzyme in microsomal fractions. This study has confirmed previous reports of the in vivo tumour promoting effects of dietary EP As/PUP As and the tumour growth inhibitory effects of Asc. The in vitro cell growth inhibitory effects of Asc and the EP As also confirm the results of previous reports. Previous studies investigating possible interactions between Asc and EP As/PUP As in influencing tumour cell growth could not be located in the relevant literature. This study may therefore be one of the first investigations of any such interaction between these nutrients in tumour cells. While this study was not able to identify the mechanisms involved in the different tumour promoting or tumour growth inhibitory effects of the two nutrients in the two systems, it did eliminate a number of potential mechanisms. The results of this study also emphasise the difficulty of attempting to compare the results of in vitro and in vivo studies.
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- Date Issued: 1990
An investigation of the orientation of certain long-chain fatty acids at the air-water interface
- Authors: Saayman, Henry Martin
- Date: 1962
- Subjects: Fatty acids , Surface chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4496 , http://hdl.handle.net/10962/d1013117
- Description: The results obtained for the cross-sectional areas of the series of long-chain fatty acids may best be summarized with the aid of Graph 9. This graphical representation of the molecular areas, in Ų , against the chain length (n), of the fatty acid molecules, illustrates variation of the areas with chain length for the series in recrystallized form, and also for selected samples in the zone purified and vacuum distilled forms. On the graph, the limits of variation of the molecular areas have been represented as lines of a length corresponding to twice the standard deviation (2S). This is to give representation that the standard deviation may be positive or negative in relation to the mean. For molecules with n odd and lying between 15 and 19, the molecular area decreases. This may be due to the effect of 3 factorsg (1) A general decrease in lateral translation because of the increasing molecular mass (translational kinetic energy per molecule = ½ mc ⁻²), resulting in closer spacing of molecules. (2) A general, but steady decrease in the angle of tilt of the molecules which thus tend to be held more erect in the condensed film. (3) A general decrease in the precessional motion of the hydrophobic chain groups. For molecules with n odd and between 19 and 23, the molecular areas increase probably due to the steady increase in molecular mass causing the long chains to commence to buckle, tilt or topple in their upper regions. This tilting becomes greater because of the increasing gravitational effect on the heavier molecules which tends to make them assume a flatter posture in relation to the surface. The lower values observed for margaric and nonadecanoic acids, may be due to increasing symmetry in the chain, with corresponding economy in packing in condensed monolayers. This effect may be connected with increasing cylindrical symmetry of the hydrocarbon chain for even values of n. The results of this investigution, incomplete as it is, - serve to indicate what might reasonably be expected to happen in the orientation of these fatty acids in monolayers. Further work, especially on a greater range of acids with even n, is clearly necessary in order to establish the tentative ideas which have been suggested. However, in the present research, work was limited to those acids in the series which were obtainable without undue difficulty or delay, those which would spread readily under the conditions of experiments carried out at 20°C, and those which could be purified relatively easily. The acids below n = 15 in the series were found to be too soluble in aqueous substrates, at operating temperatures of 20°C, to yield reliable evidence with the Langmuir trough technique. The acids above n = 23 were unobtainable commercially and the synthesis of those acids from the lower members in the series presented problems of isolating the required specimens and difficulty in purifying these, which were considered b be beyond the scope of the present research. Summary and conclusion, p. 122.
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- Date Issued: 1962