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The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein
Thesis (MScAgric)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613936582393856 |
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| access_status_str | Open Access |
| author | Van der Westhuizen, Isak Andries Nicolas |
| author2 | Van Zyl, Johan Hendrik Combrink
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| author_browse | Van Zyl, Johan Hendrik Combrink
Van der Westhuizen, Isak Andries Nicolas |
| author_facet | Van Zyl, Johan Hendrik Combrink
Van der Westhuizen, Isak Andries Nicolas |
| author_sort | Van der Westhuizen, Isak Andries Nicolas |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132354 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:44:04.029Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132354 The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein Van der Westhuizen, Isak Andries Nicolas Van Zyl, Johan Hendrik Combrink Kriel, G. V. Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Lambs Feedlots Lambs -- Feeding and feeds Bioflavonoids -- Metabolism Proteins in animal nutrition Antioxidants -- Metabolism Vitamin A Vitamin E UCTD Thesis (MScAgric)--Stellenbosch University, 2025. van der Westhuizen, I. A. N. 2025. The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/80d31080-4741-4521-856b-400dbf0353fb ENGLISH ABSTRACT: Subjecting lambs to an intensive production system increases their exposure to conditions conducive to oxidative stress. To counteract this, vitamin A and E are typically supplemented in lamb feed for its antioxidant properties. However, the unstable prices of these vitamins can lead to high market costs for feed manufacturers, necessitating the search for alternative antioxidants to stabilize or reduce feed costs. Bioflavonoids have been identified as a less expensive source of antioxidants that could ultimately lower total feed costs. Improved growth rates of feedlot animals reduce the time required to reach slaughter weight, thereby lowering feed costs and enhancing annual throughput, which in turn boosts profitability. Protein sources with a higher RUP leads to improved growth rates although feed commodities providing rumen undegradable protein (RUP) are typically costly and significantly impact overall feed expenses. Optimizing protein utilization can either enhance animal productivity or reduce the amount of protein needed in the diet. Given that dietary protein is a critical and expensive component of ruminant nutrition, optimizing its use is essential for improving production efficiency and profitability. Bioflavonoids as condensed tannins have been proposed as a method to protect proteins from ruminal degradation, potentially increasing the availability of amino acids for absorption in the small intestine and improving protein utilization efficiency. This study investigated the effects of partially replacing vitamins A and E with a commercial bioflavonoid in the diets of feedlot-reared lambs as well as the effect of bioflavonoids on OM and CP degradation in the rumen. The first experiment included four dietary treatments: a positive control (100% normal vitamin A and E levels with 0g bioflavonoids), treatment 2 (100% normal vitamin A and E levels with 200g/ton bioflavonoids), treatment 3 (50% normal vitamin A and E levels with 200g/ton bioflavonoids), and treatment 4 (0% normal vitamin A and E levels with 200g/ton bioflavonoids). Normal vitamin A levels were set at 100 retinol equivalents/kg of BW and normal vitamin E levels at 15 IU/kg DM. Results showed no significant differences in growth and production parameters among the four dietary treatments. However, animals receiving treatment 4 exhibited a significantly lower (P < 0.05) margin above specified cost compared to those in treatments 1 and 3. This suggests that it is possible to partially replace vitamin A and E with bioflavonoids in the diet of feedlot lambs without negatively affecting production while maintaining similar profit margins. Consequently, producers could consider using bioflavonoids as an alternative antioxidant when the prices of vitamins A and E increase due to market demands. The second study investigated the effect of condensed tannins sourced from Acacia mearnsii on the in vitro degradability of dry matter and protein, using sunflower meal as the substrate at inclusion rates of 0, 0.2, 2, and 5 g CT/kg DM, with assessments at 8 and 48 hours. The results revealed no significant differences in dry matter or crude protein disappearance among the treatments at either time point. These findings suggest that the application of condensed tannins at levels up to 5 g/kg DM did not effectively bind dry matter or protein within the rumen. Further research is recommended to explore higher inclusion levels of condensed tannins from Acacia mearnsii on both the effect as a natural antioxidant and its protein binding ability in the rumen. AFRIKAANSE OPSOMMING: Die blootstelling van lammers aan 'n intensiewe produksie-stelsel verhoog hul blootstelling aan toestande wat oksidatiewe spanning bevorder. Om dit te bekamp, word vitamiene A en E gewoonlik in lammers se voer aangevul vir hul antioksidantiese eienskappe. Die onstabiele pryse van hierdie vitamiene kan egter lei tot hoë mark koste vir voerprodusente, wat die soektog na alternatiewe antioksidante noodsaak om voer koste te stabiliseer of te verminder. Bioflavonoïede is geïdentifiseer as 'n goedkoper bron van antioksidante wat uiteindelik die totale voerkoste kan verlaag. Verbeterde groeitempo’s van diere in voerkrale en dit verminder die tyd wat nodig is vir diere om slag gewig te bereik, wat sodoende voerkoste verlaag en jaarlikse deurgang verbeter, wat weer winsgewendheid verhoog. Proteïenbronne met 'n hoër RUP lei tot verbeterde groeitempo’s alhoewel voer kommoditeite wat rumen ondegradeerbare proteïen (RUP) verskaf, gewoonlik duur is en 'n beduidende impak op algehele voerkoste het. Die optimalisering van proteïen gebruik kan óf diere produksie verbeter óf die hoeveelheid proteïen wat in die dieet benodig word, verminder. Aangesien dieet proteïen 'n kritieke en duur komponent van herkouer voeding is, is die optimalisering daarvan noodsaaklik vir die verbetering van produksie doeltreffendheid en winsgewendheid. Bioflavonoïede as gekondenseerde tanniene is voorgestel as 'n metode om proteïene te beskerm teen ruminale afbraak, wat moontlik die beskikbaarheid van aminosure vir opname in die dunderm verhoog en proteïen gebruik doeltreffendheid verbeter. Hierdie studie het die effekte ondersoek van die gedeeltelike vervanging van vitamiene A en E met 'n kommersiële bioflavonoïed in die diëte van voerkrale lammers sowel as die effek van bioflavonoïede op OM en CP afbraak in die rumen. Die eerste eksperiment het vier diet behandelings ingesluit: 'n positiewe kontrole (100% normale vitamien A en E vlakke met 0g bioflavonoïede), 'n negatiewe kontrole (100% normale vitamien A en E vlakke met 200g/ton bioflavonoïede), behandeling 3 (50% normale vitamien A en E vlakke met 200g/ton bioflavonoïede), en behandeling 4 (0% normale vitamien A en E vlakke met 200g/ton bioflavonoïede). Normale vitamien A vlakke was gestel op 100 RE/kg BW en normale vitamien E vlakke op 15 IU/kg DM. Resultate het geen beduidende verskille in groei- en produksieparameters tussen die vier diet behandelings getoon nie. Diere wat behandeling 4 ontvang het, het egter 'n beduidend laer (P < 0.05) marge bo gespesifiseerde koste getoon in vergelyking met dié in behandelings 1 en 3. Dit dui daarop dat dit moontlik is om vitamien A en E gedeeltelik met bioflavonoïede in die dieet van voerkrale lammers te vervang sonder om produksie negatief te beïnvloed terwyl soortgelyke winsmarges gehandhaaf word. Gevolglik kan produsente oorweeg om bioflavonoïede as 'n alternatiewe antioksidant te gebruik wanneer die pryse van vitamiene A en E verhoog weens markvraag. Die tweede studie het die effek van gekondenseerde tanniene afkomstig van Acacia mearnsii op die in vitro degradeerbaarheid van droë materiaal en proteïen ondersoek, met sonneblom-oliekoek as die substraat by insluitngs vlakke van 0, 0.2, 2, en 5 g CT/kg DM, met evaluasies by 16 en 48 uur. Die resultate het geen beduidende verskille in droë materiaal of ru-proteïen verdwyning tussen die behandelings op enige tydstip getoon nie. Hierdie bevindinge dui daarop dat die toepassing van gekondenseerde tanniene op vlakke tot 5 g/kg DM nie doeltreffend was om droë materiaal of proteïen binne die rumen te bind nie. Verdere navorsing word aanbeveel om hoër inlywingsvlakke van gekondenseerde tanniene van Acacia mearnsii te ondersoek, beide oor die effek as 'n natuurlike antioksidant en sy proteïenbindende vermoë in die rumen. Masters 2025-06-04T13:26:20Z 2025-06-04T13:26:20Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132354 en Stellenbosch University 118 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Lambs Feedlots Lambs -- Feeding and feeds Bioflavonoids -- Metabolism Proteins in animal nutrition Antioxidants -- Metabolism Vitamin A Vitamin E UCTD Van der Westhuizen, Isak Andries Nicolas The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title | The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title_full | The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title_fullStr | The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title_full_unstemmed | The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title_short | The role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| title_sort | role of bioflavonoids as an antioxidant in feedlot lambs and the effect it has on rumen degradable protein |
| topic | Lambs Feedlots Lambs -- Feeding and feeds Bioflavonoids -- Metabolism Proteins in animal nutrition Antioxidants -- Metabolism Vitamin A Vitamin E UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132354 |
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