Digitized by Kansas Correctional Industries

Three studies were conducted to determine the effects of roasting on ruminal degradability of sunflower seeds and the effects of feeding roasted sunflower seeds on ruminal fermentation, nutrient digestibility and milk yield and composition of dairy cows. Experimental treatments were a control diet with no added sunflower seed, a raw sunflower seed diet and a roasted sunflower seed diet. Sunflower seed diets contained 6% fat whereas the control diet contained 3% fat. In study one, two ruminally fistulated cows were used in a randomized complete block design to determine the effects of roasting on ruminal degradation of sunflower seeds. In the second study, three ruminally cannulated lactating Holstein cows were used in a 3 x 3 Latin square experiment to determine the effects of dietary treatments on ruminal fermentation and total tract nutrient utilization. In the last study, three primiparous and six multiparous Holstein cows were used in three 3 x 3 Latin squares to determine the effects of dietary treatments on milk yield and composition.

Three studies were conducted to determine the effects of nonstructural carbohydrate (NSC) sources on performance of dairy cows fed sunflower seeds. In the first study, the effects of NSC source on dry matter (DM) intake, milk yield and milk fatty acid composition were evaluated using fifteen lactating Holstein cows in a 3 x 3 Latin square design. In the second study, fifteen lactating Holstein cows were used in a completely randomized design to determine the effects of NSC on the total tract nutrient utilization. The third study was designed to determine in situ ruminal degradability of DM, CP, NDF and starch of dietary treatments of study one and two, where two ruminally fistulated cows used in a randomized complete block design. Results of the in situ ruminal degradability trial showed that BC and CBC had similar effective ruminal degradability of DM and CP which was higher (P < 0.05) than that of CC. However, starch ruminal degradability was highest for BC, intermediate for CBC and lowest for CC. Sources of NSC had no effect on the NDF in situ ruminal degradability. It was concluded that changing the source of NSC and feeding sunflower seeds can modify milk fatty acid composition without any adverse effect on milk yield or milk components, and with no detrimental effect on nutrients utilization. (Abstract shortened by UMI.)

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Thesis (MScAgric)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: 1. The effect of heat-treatment and dehulling of full-fat soya (Glycine max) on AMEn' amino acid availability and broiler performance. Heat treatment and dehulling of full-fat soya were evaluated in terms of their effect on AMEn, apparent amino acid availability and broiler performance. Four products were tested: raw whole soya (RWS), raw dehulled soya (RDS), extruded whole soya (EWS) and extruded dehulled soya (EDS). Trials were conducted to determine AMEn values and apparent amino acid availability of the products. A 42-day broiler trial was conducted to measure the effect of extrusion and dehulling on broiler performance. Test products were added to the diets at levels up to 263.2 g/kg in the starter diet and 260.0 g/kg in the finisher diet. Results indicated that extrusion cooking improved AMEn and apparent amino acid availability. This was reflected in the improved performance of broilers fed extruded soya as compared to raw soya. Increasing amounts of RWS and RDS led to decreases in mass and intake and poor feed conversion ratio (FeR) due to the presence of anti-nutritional factors. Broilers fed EWS were heavier, consumed more feed and had better FeR than those fed RWS or RDS. Dehulling improved AMEn (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) and rendered a product with slightly higher levels of total amino acids. Broiler performance did not reflect this as there was no difference in mass, intake or FeR between broilers fed increasing levels of EWS or EDS. Lysine and arginine were less available in EDS than EWS indicating the possible over-cooking of EDS. Levels of EWS and EDS of 263.2 g/kg in the starter and 260.0 g/kg in the finisher supported maximum broiler performance. 2. The effect of heat-treatment and dehulling of full-fat sunflower (Helianthus annuus) on AMEm amino acid availability and broiler performance. Heat treatment and dehulling of full-fat sunflower were evaluated in terms of their effect on AMEn, apparent amino acid availability and broiler performance. Four products were tested: raw whole sunflower (RWSF), raw dehulled sunflower (RDSF), extruded whole sunflower (EWSF) and extruded dehulled sunflower (ED SF). Trials were conducted to determine AMEn values and apparent amino acid availability of the products. A 42-day broiler trial was conducted to measure the effect of expansion and dehulling on broiler performance. Test products were added to the diets at levels up to 115.0 glkg in the starter diet and 181.5 glkg in the finisher diet. Dehulling rendered a product with higher crude protein, ether extract, amino acid and AMEn values. AMEn was only slightly improved by expansion. The AMEn values obtained were: RWSF: 16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg. Dehulling had no effect on apparent amino acid availability. Expansion did not affect apparent amino acid availability of dehulled full-fat sunflower but had a negative influence on apparent amino acid availability of whole sunflower seeds. This highlights the possible dangers of reduced protein quality as a result of overprocessing. No differences were observed in terms of mass, intake and feed conversion ratio of broilers fed any of the products during the 42-day broiler growth trial. All products supported optimum broiler performance at levels up to 115.0 glkg in the starter diet. For the finisher diets, optimum performance was maintained at levels of 181.5 glkg, for RDSF and EDSF, while performance of broilers fed RWSF and EWSF was optimal up to 145.2 glkg. / AFRIKAANSE OPSOMMING: 1. Die invloed van hitte-behandeling en ontdopping van volvetsojabone (Glycine max) op SMEm skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Hitte-behandeling en ontdopping van volvetsojabone is ge-evalueer in terme van hul invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn) waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte is getoets: rou heel sojabone (RWS), rou ontdopte sojabone (RDS), geekstrueerde heel sojabone (EWS) en geekstrueerde ontdopte sojabone (EDS). Proewe is uitgevoer om die SMEn waardes en skynbare aminosuur beskikbaarheid van die vier produkte te bepaal. Gedurende 'n braaikuikengroeitoets van 42 dae is die invloed van hittebehandeling (ekstrusie) en ontdopping op braaikuikenprestasie gemeet. Die vier toetsprodukte is ingesluit in die aanvangsdieet teen peile van tot 263.2 g/kg en teen peile van tot 260.0 g/kg in die afrondingsdieet. Resultate het getoon dat ekstrusie die SMEn waardes en skynbare aminosuur beskikbaarheid verbeter het. Braaikuikens wat geekstrueerde soja ontvang het, het beter gepresteer as braaikuikens wat rou soja ontvang het. Verhoogte insluitings van RWS en RDS het gelei tot verlagings in massa toename en voerinname en swak voeromsetverhoudings (VOV), as gevolg van die teenwoordigheid van anti-voedings faktore. Braaikuikens wat EWS ontvang het, was swaarder, het meer ingeneem en het beter vav gehad as die wat RWS of RDS ontvang het. Ontdopping het SMEn verhoog (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) en ontdopte produkte het klein hoeveelhede meer aminosure bevat. Dit het egter nie in braaikuikenprestasie gewys nie. Daar was geen verskille in massa, voerinname en vav tussen braaikuikens wat EWS of EDS ontvang het. Lisien en arginien was minder beskikbaar in EDS as EWS wat op die moontlike oorprosessering van EDS dui. Vlakke van EWS en EDS van 263.2 g/kg in die aanvangsdieet en 260.0 g/kg In die afrondingsdieet het maksimale braaikuikenprestasie ondersteun. 2. Die invloed volvetsonneblosaad van hitte-behandeling (Helianthus annuus) en ontdopping van op SMEo, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Hitte-behandeling en ontdopping van volvetsonneblomsaad is geevalueer in terme van hul invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn) waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte is getoets: rou heel sonneblomsaad (RWS), rou ontdopte sonneblomsaad (RDS), geekspandeerde heel sonneblomsaad (EWS) en geekspandeerde ontdopte sonneblomsaad (EDS). Proewe is uitgevoer om die SMEn waardes en skynbare aminosuur beskikbaarheid van die vier produkte te bepaal. Gedurende 'n braaikuikengroeitoets van 42 dae is die invloed van hitte-behandeling (ekspansie) en ontdopping op braaikuikenprestasie gemeet. Die vier toetsprodukte is ingesluit in die aanvangsdieet teen peile van tot 115.0 g/kg en teen peile van tot 181.5 g/kg in die afrondingsdieet. Ontdopte sonneblomsaad het hoer peile van ruproteien, eter-ekstrak en aminosure as heel sonneblomsaad. SMEn waardes is ook hoer vir ontdopte sonneblomsaad. Hitte-behandeling het SMEn waardes effens verhoog. Die bepaalde SMEn waardes is as volg: RWSF: 16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg. Ontdopping het geen invloed op skynbare aminosuur bekikbaarheid gehad nie. Skynbare aminosuur beskikbaarheid van ontdopte sonneblomsaad IS me deur hitte-behandeling beinvloed nie, terwyl die van heel sonneblomsaad negatief beinvloed is. Dit beklemtoon die gevare van verswakte proteien kwaliteit as gevolg van oor-prosessering. Geen verskille is opgemerk in terme van massa, voerinname en voeromset verhouding (VOV) tussen die vier produkte gedurende die braaikuikengroeitoets van 42 dae. Alle produkte het maksimale braaikuiken prestasie ondersteun in die aanvangsdieet teen vlakke van 115.0 g/kg. In die afrondingsdieet het RDSF en EDSF optimale braaikuikenprestasie onderhou teen vlakke van 181.5 g/kg, terwyl RWSF en EWSF net t

Sunflower (Helianthus annuus L.) is one of the most important oil crops in South Africa and genetic improvement for grain yield and oil-content was initiated in the country in the early 1970s. Commercial production of sunflower in South Africa is done under natural rainfall conditions in areas where frequencies of drought are high hence the requirement for drought tolerant cultivars. An assessment of the genetic gains in seed and oil yield achieved since 1970, the effects of re-cycling inbred lines and strategies for developing drought tolerant sunflower cultivars has not been done for South African sunflower breeding programmes. Two data-sets were used for the genetic gain studies: side-by-side evaluation of historical and current sets of popular cultivars in the same environment under one set of trial management practices; and yield trends in commercial farmers’ fields based on annual production estimates. The estimated relative genetic gain for seed yield based on side-by-side trials was 1.5% year−1 and the relative gain in seed yield per year under commercial production was 1.9% year−1. The contribution of new cultivars to total seed yield progress in sunflower were 56.3% for the period 1970 to 1989; 23.9% from 1990 to 2009 and the mean over the four decades under consideration from 1970 to 2009 was 41.6%. Quantifying the usefulness of inbred lines in advanced cycle plant breeding was done using four base breeding populations based on: phenotypic or genetic variability; heterosis; and combining ability. Significant genetic variation was evident for seed yield and oil yield while genetic variability for oil content was low. Genetic advance (GA%), with a 10% selection intensity, was high for seed yield and oil yield for each of the four populations ranging from 36-42% and 38-43%, respectively. The GA% for oil content was low ranging from 1.3% to 5.1% indicating the need to introgress high oil content germplasm in the present breeding populations in advanced cycle pedigree breeding. Founder parent heterosis (FPH), mid-standard heterosis (MSH) and high standard heterosis (HSH) indicated that some new testcross hybrids from the advanced cycle pedigree breeding populations were performing better than their founder parents in hybrid combination as well as the standard commercial hybrid checks. From variance component analysis, general combining ability (GCA) was predominant over specific combining ability (SCA) for seed and oil yields indicating that superior hybrids can be identified based on positive and significant GCA effects of the female lines. For oil content, SCA was predominant over GCA indicating that it would be best to select for specific hybrids combinations with high oil content rather than selecting female lines with high GCA effects. Variable moisture conditions characterise the sunflower production environments in South Africa. Breeding for such environmental conditions requires a combination of strategies including use of secondary traits and developing appropriate test environments. Three secondary traits, head diameter, stem diameter and stay green canopy which are easy to measure in the field were evaluated for their appropriateness for selecting for drought tolerance under three moisture conditions: random stress environments (RSE), managed drought stress environments (MSE) and well watered nonstress environments (NSE). Type A genetic correlations indicated that stay green canopy (SG) had the potential to be used as secondary trait to indirectly improve oil yield under the three moisture conditions. The indirect selection efficiency (ISE) for SG using genetic correlations based on H2 were 0.79, 0.82 and 0.78 in the RSE, MSE and NSE, respectively, while that using genetic correlation based on h2 were 0.67, 0.98, and 0.93 in the RSE, MSE and NSE, respectively. In both cases selection in the MSE had the highest efficiency using genetic correlations based on either H2 or h2. Estimates of indirect selection based on type B genetic correlations indicated that indirect selection for oil yield (OY) in the MSE and NSE for the target RSE was as effective as direct selection of OY in the RSE based on additive genetic correlations of 0.96 obtained in both selection environments. Overall, the results from the exploratory drought tolerance study should inform the development of breeding strategies to improve drought tolerance and associated yield stability of sunflower cultivars grown in South Africa and associated environments. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Sunflower (Helianthus annuus) consists of high levels of polyunsaturated fatty acids, making its oil susceptible to oxidation. Tocopherols can retard or prevented oxidation. The aim of this study is to determine the phenotypic tocopherol (vitamin E) composition and genetic diversity of the biosynthetic pathway genes. Seeds were characterized for fatty acid and tocopherol content. A positive correlation was found between oleic acid, γ (r =0.17) and δ (r =0.23) tocopherol but none between linoleic acid and all four tocopherol derivatives. Vitamin E gene homologues were identified and a concomitant pathway constructed, with genes of interest sequenced to determine their genetic variation. A sunflower gene database was developed for these genes and used to obtain 489 SNPs and 145 indels from the accessions evaluated. Only 139 of these SNPs were located in the exon regions of the gene candidates. These exon-based SNPs may influence tocopherol flow through possible enzyme structural modifications / School of Agriculture and Life Sciences / M. Sc. (Life Sciences)