DEd (Curriculum Studies) / College students in Zimbabwe were facing many challenges in adopting proper dietary patterns which promote learning. This study sought to establish the impact of Socio-Economic factors and dietary patterns in particular on the academic performance of college students in Zimbabwe. The study established challenges that were faced by college students in making choices of dietary patterns that promote learning. Factors that influence choice of dietary patterns for college students were established in this study. The case study was Joshua Mqabuko Nkomo Polytechnic College in Zimbabwe with a population of 206 students and a sample of 102 participants was purposively selected. A mixed-methods research, using quantitative and qualitative approaches was employed and questionnaires, interviews, observation and document analysis were used to collect data. Findings are presented from both questionnaire and interview data in combination, with interview data playing the role of supplementing quantitative findings and probing detailed information. Quantitative data was analysed using the IBM SPSS Version 23.0 while qualitative data was coded into themes and synthesised into quantitative data to support or refute quantitative data. Research indicates that diet quality and overall health status of college students are among the prominent factors which contribute to poor student academic performance worldwide. The experiences and perceptions held by the college students and cooks were investigated. The main study findings showed that if students follow proper dietary patterns they may perform well in their studies since relationship between nutrition and academic work lies on the notion that a healthy body is able to maintain a healthy mind, which suggests that certain risk factors for a physically ill-health are also risk factors for cognitive impairment. This study made recommendations for dietary patterns that promote learning in academic domains. It also developed a model valuable for dietary patterns. / `

The objectives of the research were to examine the effects of high dietary levels of fibrous feeds, and of supplementation with Roxazyme® G2 (RX), on the digestive metabolic and physiological responses of growing pigs fed maize-soybean diets. The nutrient and dietary fibre (DF) composition, the swelling and water-binding capacities of maize (MM), its hominy chop (HC) and cobs (MC), dehulled soybean (dSBM) and the hulls (SH), brewer’s grains (BG), lucerne hay (LH) and wheat bran (WB) were evaluated using standard procedures. Feed fibre fractions were isolated by simulating upper tract digestion in an Ankom® DaisyII Incubator, whereby each feed was digested in pepsin (porcine, 200 FIP-U/g, Merck No, 7190), followed by pancreatin (porcine, grade IV, Sigma No P-1750), with recovery of the fibrous residues. In a third step to complete the simulated pig gastro-intestinal digestion, the pepsin-pancreatin fibre extracts were digested by RX or Viscozyme L ® V2010 (VZ). Enzyme activity was measured as the coefficients of partial degradability (solubilisation) of the washed fibre extracts. The kinetics and products of fermentation of the DF were evaluated in an AnkomRF gas production system, using buffered faecal inoculum. Among the feed ingredients, dissimilar, fibre source-dependent activities between RX (0.02 to 0.12) and VZ (0.04-0.33) were observed. The lowest RX activities were observed on the maize and soybean derived fibres, with similarly low VZ activity on MC fibre. Variation in the activity of faecal microbial enzymes was similarly indicated by the variable production of fermentation gas (51.8-299.4 mL g-1 DM) and short chain fatty acids (SCFA) (2.3-6.0 mMol g-1 DM). Soy hull, dSBH, MM and HC fibres were highly fermentable, with low fermentability of BG, MC and WB fibres. The fibres differed in the composition of fermentation SCFA, whereby SH, LH and MC shifted fermentation to Ace, and BG, dSBM, WB, MM, HC favoured Pro, while MM and HC favoured But production. The same nutritional properties were similarly evaluated in complete diets which were formulated from the ingredients for growth, and metabolic trials. For the growth trial, a standard (STD) (control), 141 g total dietary fibre (TDF) kg-1 dry matter (DM) maize-soybean growing pig diet, and five iso-nutritive, 246 g TDF kg-1 DM nutritionally balanced diets were formulated. The high DF was achieved by partial replacement of the MM and dSBM in the STD diet with MC, SH, BG, LH or WB. The differences in RX and VZ activities and in the fermentation characteristics which were observed on the fibre extracts from the high fibre ingredients were reflected in the DF from the respective complete diets in which they were included. However, the fibre from the basal dietary ingredients reduced the absolute values and the variation in the activities of RX (0.03-0.06) and VZ (0.16-0.22), and similarly reduced the variation in gas (126.6-187.6 mL g-1 DM) and SCFA (4.1-5.4 mMol g-1 DM) production of the DF from the fibrous diets. Enzyme activities on the STD DF were low for RX (0.03) and high for VZ (0.25). The STD DF produced 205.3 mL gas g-1 DM, which was similar to SH DF, and higher than all the other diets. The STD DF produced 5.0-mMol SCFA g-1 DM, which was quantitatively, and not statistically higher than the other fibres. The composition of SCFA was similar across all diets, except for the high percent Ace, with low Pro by the SH DF. Compared to the STD, the high DF diets increased percent Ace, with reduced Pro and But. The STD, MC, SH, BG, LH and WB diets were each prepared in duplicate mixes, one of which was fortified with 200 mg RX kg-1 feed (as fed). Seventy-two intact Large White X Landrace, male, 32.0 ± 5.6 kg live weight (LW) pigs were allocated to the diets in two completely randomised weight blocks in a 2 (fibre source) X 2 (enzyme) factorial arrangement. The pigs were fed ad libitum for 10 weeks. Cumulative LW gain and feed intake were measured at different stages of growth, and at slaughter. Apparent total tract digestibility (ATTD) of nutrients was estimated at 65-70 kg LW, using 0.2% (as fed) chromium oxide as the indigestible marker. Ileal tissue was sampled 50 cm above the ileo-caecal valve, on which villi height and area, and crypt depth were evaluated by computerised image analysis. Blood was sampled at slaughter from the severed vena jugularis, 16 hours after feeding. Serum urea, creatinine, triglycerides, glucose, and total cholesterol were analysed chemically. The serum metabolome was further explored using Proton Nuclear Magnetic Resonance Spectroscopy (1H -NMRS). There was fibre X RX interaction for villi height, whereby the enzyme reduced the villi height in pigs on the SH, STD and WB diets, with an opposite effect on pigs on the MC, BG, LH diets. The soluble fibre content was negatively correlated with crypt depth. Chemical analysis did not detect differences in metabolite concentration between the STD and the high fibre diets. However, more serum cholesterol was observed in pigs fed the WB compared to the LH and MC diets. 1H-NMRS indicated that feeding pigs the WB diet increased serum Cys and His, while supplementation of RX increased serum formate, glucose, and urea. There was diet X enzyme interaction for fructose, glucose, Arg, Cys, Ser, and Trp, whereby RX increased the levels in pigs on MC and WB, with an opposite effect in pigs on the other diets. There was large DF source-dependent variation among diets in ATTD of DM (0.80-0.85), organic matter (OM) (0.81-0.87), gross energy (GE) (079-0.85) and CP (0.81-0.85), whereby, relative to the STD diet, high DF reduced the ATTD of DM (all diets except SH), organic matter (OM) and energy and CP (all diets except the MC). Positive correlation was observed between fermentability and the ATTD digestibility of DM, OM, energy, ADF, NDF, and fat. Negative correlation was observed between the swelling capacity and the ATTD of DM, OM, energy and protein, between DF solubility and DM, OM, protein, ADF and NDF, and between water binding capacity and ATTD of DM and OM, energy and NDF. At slaughter, there was similarly large, and DF source-dependent variation among the high fibre diets in feed intake (2.31-2.71 kg as fed day-1), live weight gain (0.75-0.86 kg day-1), and feed: gain ratio (2.73-3.00). Corresponding values for the STD diet were 2.44 kg day-1, 0.83 kg day-1and 2.86 kg day-1, respectively. Relative to the STD, LH reduced feed intake and live weight gain, and MC increased the feed: gain ratio. Predictions based on the in vitro fermentability of DF and feed intake suggested that due to poor fermentability, and or restriction of feed intake, relative to a standard fibre diet, high dietary levels of MC, WB and BG may reduce fermentation in the lower gut, while similar dietary levels of SH and LH may result in substantial increases in fermentation. At 50 kg LW, the fermentability of DF was positively correlated with feed intake and with weight gain, while water binding capacity and solubility of DF were negatively correlated with feed intake. At slaughter, the solubility of DF was negatively correlated with feed intake and feed: gain ratio. Large variation among the high fibre diets was also observed in the slaughter weight (89.2-96.8 kg), dressing % (68.6-76.4), meat colour (80.4-82.3), lean % (69.5-71.2), and fat % (10.1-12.6). In comparison, pigs on the STD diet scored 94.7 kg slaughter weight, 75.1% dressing, 81.6 cm carcass length, 82.5 meat colour, 68.4% lean, and 15.0% fat. Relative to the STD, LH reduced dressing and fat %. Lucerne hay and WB increased the lean%. For the metabolic trial, two iso-nutritive, mixed high fibre (319 g TDF kg-1 DM), nutritionally balanced diets were formulated to contain DF of high (HF) versus low (LF) fermentability. The diets had similar content of soluble DF and similar swelling and water binding capacities. Viscozyme was more active than RX on both the HF (0.20 versus 0.04) and the LF (0.17 versus 0.07) DF. The combination of RX and VZ statistically increased the enzyme activity on the HF (0.25) and quantitatively increased enzyme activity on the LF (0.18) DF, suggesting additive or synergistic effects. More gas was produced by the HF (159.5 mL g-1 DM) compared to the LF DF (96.6 mL g-1 DM). More SCFA were produced by HF (5.0 mMol g-1 DM), compared to the LF DF (3.6 mMol g-1 DM). Compared to the STD, HF DF increased percent Ace, with reduced Pro and But. The LF DF increased percent Ace, with quantitative, and not statistical reduction of Pro and But. In a metabolic trial, the HF and LF diets, and their duplicates containing 0.270 g RX kg-1 DM of feed (as fed) were fed ad libitum to eight ileum T-cannulised, intact Large White X Landrace male pigs weighing 65.0 ± 5.1 kg. The diets were allocated to the pigs in a duplicate 4 x 4 Latin Square design, in a 2 (enzyme) x 2 (fermentability) factorial arrangement. Each period consisted of two weeks of adaptation followed by five days of sampling. The ileal digesta was collected in each period and was similarly subjected to the fermentation test. Apparent ileal digestibility (AID) and ATTD were determined using 0.2% (as fed) chromium oxide as the indigestible marker. N excretion in faeces and urine were measured, and N retention was calculated. Blood was sampled by vena jugularis puncture on the last day of each period. Two blood samples were collected, the first 15 hours after removal from feed (15-hour serum), and the second 3 hours after re-introduction to feed (3-hour serum). Serum metabolites were evaluated by both chemical analyses and by 1H-NMRS, as described for the growth trial. Roxazyme did not affect the fermentation characteristics of the ileal digesta. In similar proportion to the fermentability of the PP digesta, the HF ileal digesta was more fermentable (65.4 mL gas g-1 DM and 6.1 mMol SCFA g-1 DM) than the LF ileal digesta (46.7 mL gas g-1 DM and 4.4 mMol SCFA g-1 DM SCFA). Prediction based on the in vitro fermentability of DF and feed intake suggested the HF diet could support one half times more fermentation in the lower gut compared to the LF diet. The HF diet had higher AID of DM (62.5 vs. 58.6), OM (65.6 vs. 62.1), energy (64.4 vs. 61.0), fat (85.8 vs. 81.7) and ash (41.8 vs. 32.7). The AID of HO-Pro, Met and Val were higher for the LF diet. There was diet X enzyme interaction on the AID of Met, whereby the RX reduced the AID of met in the LF diet, and not that of the HF diet. The ATTD was higher for the HF diet for DM (74.2 vs. 68.4), NDF (64.7 vs. 57.4), and ADF (35.1 vs. 21.0). There was positive correlation between the fermentability of DF and the AID DM, OM, ash, ash, fat and energy. The solubility of DF was negatively correlated with the AID of DM, OM, ash, fat, ADF and energy, and with the ATTD of DM, OM, ash, fat, energy, NDF, and ADF. Negative correlation was also observed between the swelling capacity of DF and the AID of protein, Trp and Lys. The solubility of DF was positively correlated with Ser, Ala, Val, Iso-Leu and His. There was diet X enzyme interaction for urea in the 15- hour serum, whereby RX tended to reduce the urea in the LF diet, while it increased that of the HF diet. Fermentability negatively correlated with urea in the 15- hour serum, and positively correlated with serum glucose in the 3-hour serum. In the 3-hour sample, 1H-NMRS indicated higher fucose, Pro and cholesterol in the LF diet. 1H-NMRS also indicated fermentability x RX interaction for Ser, Tyr, Lys, creatine, and possibly, glucose or fructose, glycerol or Gly and His or Arg, whereby RX increased the levels in the LF diets, with opposite effect in the HF diet. In conclusion, enzyme activities and fermentability were higly variable among different DF sources, and the effects were evident in the fibrous complete diets. The results of the in vitro studies supported the application of the methods to formulate fermentable insoluble fibre-rich, maize-soybean-mixed co-product diets. Correlation analyses suggested that DF fermentability, and solubility, swelling and water binding capacities explained significant proportions of the variances of the metabolic and physiological responses of the pigs to different feeds. Predictions based on the in vitro fermentability of DF and feed intake suggested that a strategy whereby pig diets are enriched in DF after the feedstuffs are screened on DF fermentability could substantially increase fermentation in the lower gut. Overall, the results suggested that productivity can be maintained in growing pigs fed diets containing up to twice the standard levels of DF, provided producers target co-product feeds that contain highly fermentable DF. The use of RX to improve nutrient digestion and to stimulate gut fermentation was not justified. / Environmental Sciences / Ph.D. (Environmental Sciences)

Vertical transmission of HIV is still a growing concern in South Africa. Breastfed infants are still at risk as HIV is present in breast milk, leaving HIV-positive mothers unsure of the best feeding option for their infants. However, there are various infant feeding techniques that HIV-positive mothers can use to supplement breastfeeding and flash-heat is one of them. Flash-heat is heat treating expressed breast milk to deactivate HIV for infant feeding. This study explored the possibility of HIV-positive mothers to practice flash-heating method for their infants exclusively for four months as a strategy to prevent vertical transmission of HIV. A descriptive, explorative and contextual design using a mixed method was used to obtain data from mothers in a post natal ward at Tembisa hospital. The mixed method used was useful in identifying the number of HIV-positive mothers who would adopt the flash-heat technique, the characteristics of mothers whom the technique could be promoted to, the factors that influence/affect the choice of infant feeding for these mothers, as well as their feelings associated with the feeding technique. Most (74%) mothers had a positive response to the flash-heat technique compared to 10% who were uncertain. They believed that heat treating their breast milk would result in their infants being HIV-free. In addition they believed that this method was cheaper than formula feeding and expressed positive feelings about touching their breast milk while expressing with no adverse feelings of expressing into a glass jar. Furthermore, findings of this study indicated that HIV-positive mothers in a public health facility would adopt flash-heat as an alternative infant feeding method. Thus practical guidelines to promote this feeding method were proposed. The proposed draft guidelines which promote the use of the flash-heat infant feeding method for HIV-positive mothers in public sector facilities will be communicated to relevant authorities such as the National Department of Health. These guidelines support the new policy shift to exclusive breastfeeding as a child survival strategy in South Africa. / Health Studies / D.Litt. et Phil. (Health Studies)

Thesis (MPhil) Stellenbosch University, 2014 / ENGLISH ABSTRACT: In an increasingly complex world where food security remains a challenge in many areas and especially Africa; it is essential to educate children about food – from production to consumption; and to ensure they eat enough as this is a crucial factor for concentration and learning abilities. How can we teach children about food in a sustainable way? This study focuses on schools in Tigray, Northern Ethiopia, which have a school feeding programme, school garden and nutrition curriculum. The question studied is: To what extent do two primary schools in central- and east Tigray (North Ethiopia) integrate the feeding scheme, school garden and nutrition curriculum? The methodology chosen is a case study and the empirical data was collected through interviews, surveys and observations. Principals of 14 schools were interviewed about the school gardens, curricula and school gardens. Two schools were then selected for a further in-depth research. The school gardens, mostly initiated by the staff, serve the purpose of creating income for the school and teaching students the skills of gardening. The curriculum is standard for Tigray and focuses on different food types and creating a balanced diet. The school food in most schools is provided by the World Food Programme (WFP), but some exceptions exist. This research shows that integration between the three objectives will be beneficial. Obstacles include getting the staff ‘on board’ as a priority and controlling the unification of the three, for example schools feel that they have less ownership over the feeding scheme because it is organised by an external NGO. This study suggests stakeholders view school gardens, nutrition education and school feeding schemes under one umbrella for the ultimate benefit of creating a sustainable model to teach about food. The case study provides an insight to the specific challenges in Tigray, Ethiopia but important conclusions can also be generalised. / AFRIKAANSE OPSOMMING: In ’n toenemend komplekse wêreld waar voedsel sekuriteit in baie gebiede, veral in Afrika ’n uitdaging bly, is dit baie belangrik om kinders oor voedsel op te voed - vanaf produksie tot by die verbruik daarvan, en ook om seker te maak dat hulle genoeg eet, wat baie belangrik is vir konsentrasie en die vermoë om te leer. Hoe kan ons kinders op ’n volhoubare manier leer oor voeding? Hierdie studie fokus op twee skole in Tigray, in Ethiopië wat skoolvoedingskemas, skooltuine en voedingkurrikula het. Die vraag wat gevra is, is: Tot watter mate integreer hierdie twee skole in Tigray die voedingskemas, die skooltuine en die voedingkurrikula? Die gekose metodologie is ’n gevallestudie. Empiriese data is ook deur middel van onderhoude, oorsigte en observasies versamel. Onderhoude oor skooltuine, voedingskemas en die kurrikula is gevoer met die skoolhoofde van 14 skole. Twee skole is toe gekies vir in-diepte navorsing. Die skooltuine bring geld in vir die skool en word ook gebruik om vir die leerling tuinmaakvaardighede aan te leer. Die kurrikulum is standaard vir die hele Tigray en word deur die Wêreld Voedsel Program verskaf. Daar is egter ’n paar uitsonderings. In hierdie navorsing is daar bewys dat die integrasie van die skooltuin, die voedingskema en die kurrikula, goeie gevolge kan hê. Dit is egter belangrik dat die skool personeel moet saamwerk en dat die vereniging van die drie beheer moet word. Skole voel bv. Tans dat hulle nie eienaarskap oor die voedingskema het nie, want dit word deur eksterne NROs beheer. Hierdie navorser stel voor dat die skooltuine, skoolvoedingskema en die voedingkurrikulum onder een sambreel beskou moet word met die doel om ’n volhoudbare model vir die onderrig van voeding te skep. Die gevallestudie verskaf insig in die spesifieke uitdagings in Tigray, Ethiopië, maar belangrike slotsomme kan ook veralgemeen word.

The aim of this study was to assess the dietary intake, diet-related knowledge and metabolic control in children with Type 1 Diabetes Mellitus between the ages of 6-10 years attending the Paediatric Diabetic Clinics at Grey’s Hospital, Pietermaritzburg and Inkosi Albert Luthuli Central Hospital, Durban, KwaZulu-Natal. This was a cross sectional observational study that was carried out in a total of 30 subjects out of a possible 35 subjects that qualified for inclusion in the study from both the Grey’s Hospital clinic (n=8) and IALCH clinic (n=22). The dietary intake was assessed in a total of 25 subjects using a three day dietary record (n=20) and a 24 hour recall of the third day of the record (n=16). Diet-related knowledge was assessed using a multiple choice questionnaire. Metabolic control was assessed using the most recent HbA1c and the mean HbA1c results over the previous 12 months from the date of data collection. Height and weight measurements were also carried out. Information on socioeconomic status and education status of the caregivers was obtained from 22 caregivers through follow-up phone calls. All measurements except for dietary intake were obtained from all subjects participating in the study. The mean percentage contribution of macronutrients to total energy was very similar to the International Society for Pediatric and Adolescent Diabetes (ISPAD) Consensus Guidelines (2002). The mean percentage contribution of macronutrients to total energy from the 3 day dietary records and the 24 hour recalls were as follows: carbohydrate (52% and 49%); sucrose (2% and 2%); protein (16% and 17%); fat (32% and 34%). Micronutrient intake was adequate for all micronutrients except for calcium and vitamin D which showed low intakes. The mean diet-related knowledge score for the sample was 67% with significantly higher scores in children older than 8 years of age. The latest HbA1c for the sample was 9.7% and the mean HbA1c over the previous 12 months from the date of data collection was 9.6%. There was a significant positive correlation between age of the participant and the latest HbA1c (r = 0.473; p=0.008) and a significant negative correlation between the education level of the caregivers and the latest HbA1c (r = - 0.578; p=0.005) and the mean HbA1c over 12 months (r = - 0.496; p=0.019). Significant differences were found between African and Indian children respectively for HbA1c, with higher values in African children. There was no correlation between BMI for age and latest HbA1c (r = 0.203, p=0.282) or mean HbA1c over 12 months (r = 0.101, p=0.594). Z score for BMI for age was also not correlated with latest HbA1c (r = 0.045, p=0.814) or mean HbA1c over 12 months (r = - 0.012, p=0.951). Children from the Grey’s Hospital Clinic were found to have higher HbA1c values (p=0.001) and lower diet-related knowledge scores as compared to the children from the IALCH Clinic (p=0.038). It should be noted that the ethnic and racial composition of the children attending these two clinics differed. In conclusion the macronutrient intake in this sample was found to be similar to the ISPAD Consensus Guidelines (2002) while calcium and vitamin D intakes were low. Overall this sample displayed good diet-related knowledge while metabolic control was found to be poor. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Thesis (MNutr (Human Nutrition))--University of Stellenbosch, 2006. / PROJECT AIM The aim of this qualitative cross-sectional descriptive study was to test the comprehensibility of the preliminary Food-Based Dietary Guidelines for healthy children aged 1-7 years. Objectives included assessing exposure to Food-Based Dietary Guidelines, assessing comprehension of the proposed Paediatric Food-Based Dietary Guidelines (perceptions, interpretation and understanding of terminology, concepts and descriptions), and assessing whether the guidelines can be used in meal planning. METHOD The proposed study was submitted to the Committee for Human Research, Faculty of Health Sciences, Stellenbosch University, and was subsequently approved. Focus group discussions were used to collect data. The discussions were facilitated by the investigator in either English or Afrikaans, according to a predetermined discussion guideline. Mothers with children aged 1-7 years old voluntarily participated in the study. With permission from the Department of Education, mothers were contacted via randomly chosen pre-primary schools, crèches and playgroups. Focus groups were formed on the basis of language and socio-economic status (SES), using randomly selected suburbs to represent lower, middle and upper SES groups. Sixteen focus groups were conducted: 2 pilot groups, 1 English and 1 Afrikaans lower SES, 3 English and 3 Afrikaans middle SES groups, and 3 English and 3 Afrikaans upper SES groups. RESULTS A total of 76 mothers participated in the study. On the whole, the mothers understood the proposed Paediatric Food-Based Dietary Guidelines as intended by the Paediatric Working Group. The rationale behind the guidelines was not always known, but grasped once explained. No substantial differences were found between English and Afrikaans data. Differences were found between SES groups, with the highly educated upper SES groups having a better understanding of the nutritional information than the other groups. In all groups, mothers suggested that slight changes be made to the wording of the guidelines, and that examples and additional information be given along with each of the guidelines. Overall they agreed that the proposed guidelines might prove to be useful. CONCLUSION The proposed Paediatric Food-Based Dietary Guidelines were well received by the mothers in the focus groups. The target population which would most benefit from these guidelines would be the less educated, lower SES groups, as more highly educated mothers seem to already have greater exposure to nutritional information. This study shows that once the guidelines have been modified, they may be used as a comprehensive guide for nutritional education.

Background: The health benefits and economic gains of exclusive breastfeeding for the mothers and the new-born are well-documented in the literature as discussed in the background and the rationale for this study. The effectiveness of the social cognitive based interventions in promoting breastfeeding among women in general is also documented. However, there is lack of evidence regarding social-cognitive strategies that could be used to promote exclusive breastfeeding practices among primiparous mothers in Ethiopia means that current exclusive breastfeeding promotion interventions or strategies may not produce the expected outcomes. This assumption seems to be supported by low rate of early initiation of breastfeeding in country (52.1% instead of at least 75% as recommended by WHO) and shorter period of breastfeeding (one month) among mothers in Addis Ababa (CSA and ICF 2012) despite various strategies and interventions that have been implemented. Aims: The study was conducted with the aim of determining the social-cognitive predictors of exclusive breastfeeding among primiparous mothers during the first six months post-delivery with the view of developing social-cognitive strategies to promote exclusive breastfeeding practices among primiparous mothers in Addis Ababa, Ethiopia. Research design and method: The study was carried out within the quantitative positivist paradigm. The study was divided into two phases. The researcher used quantitative longitudinal, descriptive, exploratory and correlational designs to determine the social cognitive predictors of exclusive breastfeeding among primiparous mothers in Addis Ababa, Ethiopia within the first six months post-delivery. The results of the first phase assisted the researcher to design social-cognitive strategies to promote exclusive breastfeeding among primiparous mothers using a Delphi survey. A Delphi survey design was used to assist the researcher to develop the social-cognitive strategies to promote exclusive breastfeeding among primiparous mothers. It consisted of three rounds of mailed self-completion questionnaires. The Delphi was supported with critical review and synthesis of literature throughout the strategies’ development process. Descriptive summary statistics were used to analyse the prenatal breastfeeding behaviour of 141 primiparous mothers followed from the last antenatal care visits up to six months after delivery. Bivariate correlational and multiple logistic regression analyses were used to identify the social cognitive determinants and predictors of exclusive breastfeeding within the first hour post-delivery and six months thereafter. Findings: Positive breastfeeding outcome expectancy and high breastfeeding self-efficacy were identified as the independent social cognitive predictors of exclusive breastfeeding among primiparous mothers in Ethiopia. These predictors were used to develop social cognitive strategies to promote exclusive breastfeeding, which comprise six main components: (1) scientific evidence for the strategies, (2) the rationale for the strategies, (3) the aim of the strategies, (4) the scope of the strategies, (5) the guiding principles, and (6) the key results areas. These strategies were developed and validated with the inputs from 37 experts on breastfeeding and social cognitive theory. Two key results areas (build individual capacity for exclusive breastfeeding and create an enabling environment) and five strategic objectives were formulated and validated. Conclusions: The successful implementation of the social cognitive strategies to promote exclusive breastfeeding among primiparous mothers in Addis Ababa, Ethiopia as described above will require among others (1) in-service training on social cognitive skills for healthcare providers with focus on how to build self-efficacy and outcome expectancy, (2) the development of self-efficacy and outcome expectance assessments tools relevant to the Ethiopian context, and (3) additional support and resources from the healthcare managers. Recommendations: To the researcher recommend that programs aimed at promoting exclusive breastfeeding practices among primiparous mothers should be based on the combined attributes of positive social cognitive outcome expectance and high breastfeeding self-efficacy. Further research is needed to develop assessment tools for breastfeeding self-efficacy and outcome expectancy before the implementation of the proposed strategies. / Health Studies / D. Litt. et Phil. (Health Studies)

Vertical transmission of HIV is still a growing concern in South Africa. Breastfed infants are still at risk as HIV is present in breast milk, leaving HIV-positive mothers unsure of the best feeding option for their infants. However, there are various infant feeding techniques that HIV-positive mothers can use to supplement breastfeeding and flash-heat is one of them. Flash-heat is heat treating expressed breast milk to deactivate HIV for infant feeding. This study explored the possibility of HIV-positive mothers to practice flash-heating method for their infants exclusively for four months as a strategy to prevent vertical transmission of HIV. A descriptive, explorative and contextual design using a mixed method was used to obtain data from mothers in a post natal ward at Tembisa hospital. The mixed method used was useful in identifying the number of HIV-positive mothers who would adopt the flash-heat technique, the characteristics of mothers whom the technique could be promoted to, the factors that influence/affect the choice of infant feeding for these mothers, as well as their feelings associated with the feeding technique. Most (74%) mothers had a positive response to the flash-heat technique compared to 10% who were uncertain. They believed that heat treating their breast milk would result in their infants being HIV-free. In addition they believed that this method was cheaper than formula feeding and expressed positive feelings about touching their breast milk while expressing with no adverse feelings of expressing into a glass jar. Furthermore, findings of this study indicated that HIV-positive mothers in a public health facility would adopt flash-heat as an alternative infant feeding method. Thus practical guidelines to promote this feeding method were proposed. The proposed draft guidelines which promote the use of the flash-heat infant feeding method for HIV-positive mothers in public sector facilities will be communicated to relevant authorities such as the National Department of Health. These guidelines support the new policy shift to exclusive breastfeeding as a child survival strategy in South Africa. / Health Studies / D.Litt. et Phil. (Health Studies)

The objectives of the research were to examine the effects of high dietary levels of fibrous feeds, and of supplementation with Roxazyme® G2 (RX), on the digestive metabolic and physiological responses of growing pigs fed maize-soybean diets. The nutrient and dietary fibre (DF) composition, the swelling and water-binding capacities of maize (MM), its hominy chop (HC) and cobs (MC), dehulled soybean (dSBM) and the hulls (SH), brewer’s grains (BG), lucerne hay (LH) and wheat bran (WB) were evaluated using standard procedures. Feed fibre fractions were isolated by simulating upper tract digestion in an Ankom® DaisyII Incubator, whereby each feed was digested in pepsin (porcine, 200 FIP-U/g, Merck No, 7190), followed by pancreatin (porcine, grade IV, Sigma No P-1750), with recovery of the fibrous residues. In a third step to complete the simulated pig gastro-intestinal digestion, the pepsin-pancreatin fibre extracts were digested by RX or Viscozyme L ® V2010 (VZ). Enzyme activity was measured as the coefficients of partial degradability (solubilisation) of the washed fibre extracts. The kinetics and products of fermentation of the DF were evaluated in an AnkomRF gas production system, using buffered faecal inoculum. Among the feed ingredients, dissimilar, fibre source-dependent activities between RX (0.02 to 0.12) and VZ (0.04-0.33) were observed. The lowest RX activities were observed on the maize and soybean derived fibres, with similarly low VZ activity on MC fibre. Variation in the activity of faecal microbial enzymes was similarly indicated by the variable production of fermentation gas (51.8-299.4 mL g-1 DM) and short chain fatty acids (SCFA) (2.3-6.0 mMol g-1 DM). Soy hull, dSBH, MM and HC fibres were highly fermentable, with low fermentability of BG, MC and WB fibres. The fibres differed in the composition of fermentation SCFA, whereby SH, LH and MC shifted fermentation to Ace, and BG, dSBM, WB, MM, HC favoured Pro, while MM and HC favoured But production. The same nutritional properties were similarly evaluated in complete diets which were formulated from the ingredients for growth, and metabolic trials. For the growth trial, a standard (STD) (control), 141 g total dietary fibre (TDF) kg-1 dry matter (DM) maize-soybean growing pig diet, and five iso-nutritive, 246 g TDF kg-1 DM nutritionally balanced diets were formulated. The high DF was achieved by partial replacement of the MM and dSBM in the STD diet with MC, SH, BG, LH or WB. The differences in RX and VZ activities and in the fermentation characteristics which were observed on the fibre extracts from the high fibre ingredients were reflected in the DF from the respective complete diets in which they were included. However, the fibre from the basal dietary ingredients reduced the absolute values and the variation in the activities of RX (0.03-0.06) and VZ (0.16-0.22), and similarly reduced the variation in gas (126.6-187.6 mL g-1 DM) and SCFA (4.1-5.4 mMol g-1 DM) production of the DF from the fibrous diets. Enzyme activities on the STD DF were low for RX (0.03) and high for VZ (0.25). The STD DF produced 205.3 mL gas g-1 DM, which was similar to SH DF, and higher than all the other diets. The STD DF produced 5.0-mMol SCFA g-1 DM, which was quantitatively, and not statistically higher than the other fibres. The composition of SCFA was similar across all diets, except for the high percent Ace, with low Pro by the SH DF. Compared to the STD, the high DF diets increased percent Ace, with reduced Pro and But. The STD, MC, SH, BG, LH and WB diets were each prepared in duplicate mixes, one of which was fortified with 200 mg RX kg-1 feed (as fed). Seventy-two intact Large White X Landrace, male, 32.0 ± 5.6 kg live weight (LW) pigs were allocated to the diets in two completely randomised weight blocks in a 2 (fibre source) X 2 (enzyme) factorial arrangement. The pigs were fed ad libitum for 10 weeks. Cumulative LW gain and feed intake were measured at different stages of growth, and at slaughter. Apparent total tract digestibility (ATTD) of nutrients was estimated at 65-70 kg LW, using 0.2% (as fed) chromium oxide as the indigestible marker. Ileal tissue was sampled 50 cm above the ileo-caecal valve, on which villi height and area, and crypt depth were evaluated by computerised image analysis. Blood was sampled at slaughter from the severed vena jugularis, 16 hours after feeding. Serum urea, creatinine, triglycerides, glucose, and total cholesterol were analysed chemically. The serum metabolome was further explored using Proton Nuclear Magnetic Resonance Spectroscopy (1H -NMRS). There was fibre X RX interaction for villi height, whereby the enzyme reduced the villi height in pigs on the SH, STD and WB diets, with an opposite effect on pigs on the MC, BG, LH diets. The soluble fibre content was negatively correlated with crypt depth. Chemical analysis did not detect differences in metabolite concentration between the STD and the high fibre diets. However, more serum cholesterol was observed in pigs fed the WB compared to the LH and MC diets. 1H-NMRS indicated that feeding pigs the WB diet increased serum Cys and His, while supplementation of RX increased serum formate, glucose, and urea. There was diet X enzyme interaction for fructose, glucose, Arg, Cys, Ser, and Trp, whereby RX increased the levels in pigs on MC and WB, with an opposite effect in pigs on the other diets. There was large DF source-dependent variation among diets in ATTD of DM (0.80-0.85), organic matter (OM) (0.81-0.87), gross energy (GE) (079-0.85) and CP (0.81-0.85), whereby, relative to the STD diet, high DF reduced the ATTD of DM (all diets except SH), organic matter (OM) and energy and CP (all diets except the MC). Positive correlation was observed between fermentability and the ATTD digestibility of DM, OM, energy, ADF, NDF, and fat. Negative correlation was observed between the swelling capacity and the ATTD of DM, OM, energy and protein, between DF solubility and DM, OM, protein, ADF and NDF, and between water binding capacity and ATTD of DM and OM, energy and NDF. At slaughter, there was similarly large, and DF source-dependent variation among the high fibre diets in feed intake (2.31-2.71 kg as fed day-1), live weight gain (0.75-0.86 kg day-1), and feed: gain ratio (2.73-3.00). Corresponding values for the STD diet were 2.44 kg day-1, 0.83 kg day-1and 2.86 kg day-1, respectively. Relative to the STD, LH reduced feed intake and live weight gain, and MC increased the feed: gain ratio. Predictions based on the in vitro fermentability of DF and feed intake suggested that due to poor fermentability, and or restriction of feed intake, relative to a standard fibre diet, high dietary levels of MC, WB and BG may reduce fermentation in the lower gut, while similar dietary levels of SH and LH may result in substantial increases in fermentation. At 50 kg LW, the fermentability of DF was positively correlated with feed intake and with weight gain, while water binding capacity and solubility of DF were negatively correlated with feed intake. At slaughter, the solubility of DF was negatively correlated with feed intake and feed: gain ratio. Large variation among the high fibre diets was also observed in the slaughter weight (89.2-96.8 kg), dressing % (68.6-76.4), meat colour (80.4-82.3), lean % (69.5-71.2), and fat % (10.1-12.6). In comparison, pigs on the STD diet scored 94.7 kg slaughter weight, 75.1% dressing, 81.6 cm carcass length, 82.5 meat colour, 68.4% lean, and 15.0% fat. Relative to the STD, LH reduced dressing and fat %. Lucerne hay and WB increased the lean%. For the metabolic trial, two iso-nutritive, mixed high fibre (319 g TDF kg-1 DM), nutritionally balanced diets were formulated to contain DF of high (HF) versus low (LF) fermentability. The diets had similar content of soluble DF and similar swelling and water binding capacities. Viscozyme was more active than RX on both the HF (0.20 versus 0.04) and the LF (0.17 versus 0.07) DF. The combination of RX and VZ statistically increased the enzyme activity on the HF (0.25) and quantitatively increased enzyme activity on the LF (0.18) DF, suggesting additive or synergistic effects. More gas was produced by the HF (159.5 mL g-1 DM) compared to the LF DF (96.6 mL g-1 DM). More SCFA were produced by HF (5.0 mMol g-1 DM), compared to the LF DF (3.6 mMol g-1 DM). Compared to the STD, HF DF increased percent Ace, with reduced Pro and But. The LF DF increased percent Ace, with quantitative, and not statistical reduction of Pro and But. In a metabolic trial, the HF and LF diets, and their duplicates containing 0.270 g RX kg-1 DM of feed (as fed) were fed ad libitum to eight ileum T-cannulised, intact Large White X Landrace male pigs weighing 65.0 ± 5.1 kg. The diets were allocated to the pigs in a duplicate 4 x 4 Latin Square design, in a 2 (enzyme) x 2 (fermentability) factorial arrangement. Each period consisted of two weeks of adaptation followed by five days of sampling. The ileal digesta was collected in each period and was similarly subjected to the fermentation test. Apparent ileal digestibility (AID) and ATTD were determined using 0.2% (as fed) chromium oxide as the indigestible marker. N excretion in faeces and urine were measured, and N retention was calculated. Blood was sampled by vena jugularis puncture on the last day of each period. Two blood samples were collected, the first 15 hours after removal from feed (15-hour serum), and the second 3 hours after re-introduction to feed (3-hour serum). Serum metabolites were evaluated by both chemical analyses and by 1H-NMRS, as described for the growth trial. Roxazyme did not affect the fermentation characteristics of the ileal digesta. In similar proportion to the fermentability of the PP digesta, the HF ileal digesta was more fermentable (65.4 mL gas g-1 DM and 6.1 mMol SCFA g-1 DM) than the LF ileal digesta (46.7 mL gas g-1 DM and 4.4 mMol SCFA g-1 DM SCFA). Prediction based on the in vitro fermentability of DF and feed intake suggested the HF diet could support one half times more fermentation in the lower gut compared to the LF diet. The HF diet had higher AID of DM (62.5 vs. 58.6), OM (65.6 vs. 62.1), energy (64.4 vs. 61.0), fat (85.8 vs. 81.7) and ash (41.8 vs. 32.7). The AID of HO-Pro, Met and Val were higher for the LF diet. There was diet X enzyme interaction on the AID of Met, whereby the RX reduced the AID of met in the LF diet, and not that of the HF diet. The ATTD was higher for the HF diet for DM (74.2 vs. 68.4), NDF (64.7 vs. 57.4), and ADF (35.1 vs. 21.0). There was positive correlation between the fermentability of DF and the AID DM, OM, ash, ash, fat and energy. The solubility of DF was negatively correlated with the AID of DM, OM, ash, fat, ADF and energy, and with the ATTD of DM, OM, ash, fat, energy, NDF, and ADF. Negative correlation was also observed between the swelling capacity of DF and the AID of protein, Trp and Lys. The solubility of DF was positively correlated with Ser, Ala, Val, Iso-Leu and His. There was diet X enzyme interaction for urea in the 15- hour serum, whereby RX tended to reduce the urea in the LF diet, while it increased that of the HF diet. Fermentability negatively correlated with urea in the 15- hour serum, and positively correlated with serum glucose in the 3-hour serum. In the 3-hour sample, 1H-NMRS indicated higher fucose, Pro and cholesterol in the LF diet. 1H-NMRS also indicated fermentability x RX interaction for Ser, Tyr, Lys, creatine, and possibly, glucose or fructose, glycerol or Gly and His or Arg, whereby RX increased the levels in the LF diets, with opposite effect in the HF diet. In conclusion, enzyme activities and fermentability were higly variable among different DF sources, and the effects were evident in the fibrous complete diets. The results of the in vitro studies supported the application of the methods to formulate fermentable insoluble fibre-rich, maize-soybean-mixed co-product diets. Correlation analyses suggested that DF fermentability, and solubility, swelling and water binding capacities explained significant proportions of the variances of the metabolic and physiological responses of the pigs to different feeds. Predictions based on the in vitro fermentability of DF and feed intake suggested that a strategy whereby pig diets are enriched in DF after the feedstuffs are screened on DF fermentability could substantially increase fermentation in the lower gut. Overall, the results suggested that productivity can be maintained in growing pigs fed diets containing up to twice the standard levels of DF, provided producers target co-product feeds that contain highly fermentable DF. The use of RX to improve nutrient digestion and to stimulate gut fermentation was not justified. / Environmental Sciences / Ph.D. (Environmental Sciences)

The broad objective of the study was to determine the economic value of local pigs in marketand subsistence-oriented production systems in communal areas of Southern Africa. Data were collected from 288 households to investigate farmer perceptions, effects on pig production and handling of disease outbreaks such as classical swine fever (CSF) in market- and subsistenceoriented production systems. The utilisation of local pigs in these market- and subsistenceoriented production systems in improving people‟s welfare was evaluated. Climate change was identified by farmers in these production systems as a major constraint to pig production hence an experiment was carried out in the hottest season to determine diurnal heat-related physiological and behavioural responses in Large White (LW) and South African local pigs. The same genotypes were used to determine effects of diurnal heat-related stress on their growth performance. Choice experiment was done to determine farmer preferences for local pig traits and implicit prices for these traits in CSF-affected and unaffected areas that were under subsistence- and market-oriented production systems. In this experiment, the importance of heat tolerance was assessed relative to other productive and climate change adaptation traits. Significantly more pigs were culled in the CSF-affected areas that were market-oriented (8.0 ± 1.76) than subsistence-oriented (4.1 ± 1.00) production system. The risk of parasites and disease challenges was high in subsistence-oriented production system and coastal areas. In both production systems, CSF was perceived as destructive since the culling of pigs affected pork availability and income generation. The high risk of disease outbreaks and threat of climate change caused farmers in subsistence-oriented production system to select local pigs for their adaptive traits while those in the market-oriented production system focused on productive imported pigs. Farmers (83 %) indicated that they wanted pig genotypes that were adapted to climate change effects such as hot conditions. Local pigs were found to have superior heat tolerance over LW pigs (P < 0.05) in terms of lower heart rate and skin surface temperature. Frequency per day and duration for behavioural heat loss activities such as wallowing, sleeping in a prostrate posture and sprawling in slurry were also lower (P < 0.05) for local than LW pigs. The superiority of heat tolerance of local over LW pigs was further confirmed by their uncompromised growth performance under high diurnal temperatures. The Pearson‟s product moment correlation coefficient between temperature and feed conversion ratio for LW pigs was strongly positive (r = 0.50; P < 0.001) unlike the weak and positive correlation for local pigs (r = 0.20; P < 0.05). There was a quadratic relationship between temperature and average daily gain (ADG) for both pig genotypes. The regression coefficients for ADG were higher (P < 0.001) for LW than local pigs. It was concluded that at high ambient temperatures, performance of local pigs was less compromised than for LW pigs. Although local pigs were found to be heat tolerant, results of choice experiment showed that this trait was not selected for relative to other traits. Keeping pigs that required bought-in feeds, fell sick often and produced low pork quality (eating quality based on farmer perceptions) negatively affected farmers‟ livelihoods more in subsistence- than market-oriented production system. Farmers in market-oriented production system derived more benefit from productive traits such as heavier slaughter weights and large litter size than subsistence-oriented farmers. Under the subsistence-oriented production system, farmers in CSF-affected areas placed high prices on adaptive traits than the unaffected areas. Subsistence-oriented farmers who were affected by CSF wanted a total compensation price of R10 944.00 (USD1563.43) for keeping a pig genotype with unfavourable traits when compared to R4235.00 (USD605.00) for their CSF-unaffected counterparts. Implicit prices for traits could not be determined for market-oriented production system. It was concluded that farmers in CSFaffected areas placed high economic values on pig traits than farmers from the CSF-unaffected areas. The findings suggest that adapted local pigs can be promoted in subsistence-oriented production systems while productive imported pigs and their crosses with local pigs can be kept in market-oriented production systems.