Evaluation of various Phytase enzymes for application in broiler feeding

Mushinge, Bernadette Mwansa (2015-03)

Thesis (MScAgric)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Feed costs form a major component of broiler production and the industry is always investigating ways of reducing feed costs. Phytase is an innovation that releases phosphorus from feed ingredients and as a consequence improves the nutritive value of broiler diets. A 34 day experiment was conducted to determine the effect of three different types of commercial phytase (HiPhos, OptiPhos and Quantum blue) at two levels (standard and three times the standard level) on production parameters, carcass characteristics and bone mineralization of broilers. Positive control (PC) diets were formulated based on the lower end of National Research Council (NRC) recommended values. Negative control (NC) diets were formulated on the PC diets less the matrix value for HiPhos 2000FTU (HP200). A positive control diet and negative control diet were compounded for three phases; starter, grower and finisher. Therefore eight diets were mixed: 1. Positive control (PC); 2. Negative control (NC); 3. NC + 2000FTU HiPhos (HP200); 4. NC + 1000FTU OptiPhos (OP400); 5. NC + 1000FTU Quantum blue (QB200); 6. NC + 6000FTU HiPhos (HP600); 7.NC + 3000FTU OptiPhos (OP1200) 8.NC + 3000FTU Quantum blue (QB600). The experiment involved 5120 day old broilers that were allocated to a completely randomised design with eight treatment diets and eight replications. The purpose of the study was, firstly to compare the effects of three different types of commercial phytase supplemented to maize-soya bean based diets on broiler performance outcomes. Secondly, to investigate the effects of each phytase at two inclusion levels. Thirdly, to evaluate the effects of three types of phytase on internal organs and intestinal morphology. At the end of the study, supplementation of phytase to NC diets improved live weight, average daily gains and cumulative gains. However, improvements were not comparable to those of the PC group. Breast colour, pH, and temperature, dressing percentage, internal organs, as well as thigh and wing portions were not affected by phytase inclusion. Cold carcass weight, breast and drumstick portions differed significantly between treatments. Gizzard weight expressed as a percentage of live weight differed significantly between treatments. Significant differences between treatments were also observed for intestinal morphometric observations. Phytase supplementation did not have an influence tibia length, tibia diameter, robusticity index, bone breaking strength, percent ash, percent phosphorus and percent calcium. Dry tibia weight, calcium to phosphorus ratio and the length of the tibia in relation to live weight differed between treatments. Computed tomography scans showed tibia structural abnormalities. Overall, phytase supplementation to negative control diets did not meet the phosphorus requirements for proper bone formation of broilers. In addition phytase supplementation at both inclusion levels did not pose a risk to the immune status of the broiler as internal organs were not negatively affected.

AFRIKAANSE OPSOMMING: Voerkoste is die hoof komponent van braaikuiken produksie en daarom is die industrie altyd op soek na nuwe innoverende maniere om hierdie koste te verminder. Die gebruik van fitase is so ʼn innovasie wat fosfor vanaf voerkomponente vrystel en so die voedingswaarde van die dieet verhoog. ʼn 34 dae eksperiment is uitgevoer om die invloed van drie tipes fitases (HiPhos, OptiPhos en Quantum blue) teen twee insluitingspeile (standaard en drie keer die standaard) op produksie parameters, karkas eienskappe en been mineralisering van braaikuikens te bepaal. Positiewe kontrole diëte (PK) was geformuleer gebaseer op die onderste vlakke van die Nasionale Navorsingsraad (NRC) se aanbevelingsvlakke. Negatiewe kontrole diëte (NC) is geformuleer op die PK diets minus die matriks waarde van HiPhos 2000 (HP200). ʼn Positiewe en negatiewe kontrole dieet is saamgestel vir drie fases nl. (i) aanvangs, (ii) groei en (iii) afronding. Gevolglik is daar agt eksperiementele diëte gemeng: 1. Positiewe kontrole (PK); 2. Negatiewe kontrole (NC); 3. NC + 2000FTU HiPhos (HP200); 4. NC + 1000FTU OptiPhos (OP400); 5. NC + 1000FTU Quantum blue (QB200); 6. NC + 6000FTU HiPhos (HP600); 7.NC + 3000FTU OptiPhos (OP1200) 8.NC + 3000FTU Quantum blue (QB600). Vir die eksperiment is 5 120 dagoud braaikuikens in ‘n totaal ewekansige uitleg toegedeel aan agt behandelings elk met agt herhalings. Die doel van die studie was, eerstens om die invloed van die behandelings op prestasie van braaikuikens te bepaal, tweedens om die invloed van die verskillende insluitinigspeile te bepaal en derdens om die invloed van die verskillende insluitingspeile op organe en die ingewandsmorfologie te bepaal. Aan die einde van die studie is gevind dat die aanvulling van fitases tot die NC dieet gelei het to verbeterde lewende massas, gemiddelde daaglikse toenames en kumulatiewe toenames. Hierdie verbetering was egter nie vergelykbaar met die PC nie. Kleur van die borsvleis, pH, temperatuur, uitslag persentasie, interne organe, dy en vlerk porsies was nie beïnvloed deur die behandeling nie. Gizzard massa uitgedruk as persentasie van lewende massa het egter betekenisvol verskil. Verskille is ook gevind t.o.v vir ingewandsmorfologie. Fitase aanvulling het geen invloed gehad op tibia lengte, deursnee, robuustheids indeks, been breek sterkte, persentasie as, persentasie fosfor of persentasie kalsium nie. Droë tibia massa, kalsium tot fosfor verhouding en die lengte van die tibia in verhouding tot lewende massa het verskil tussen behandelings. Gerekenariseerde tomografiese skanderings het strukturele tibia abnormaliteite aangedui. Oorhoofs kan aangeneem word dat die aanvulling van fitase ensieme teen peile tot drie keer die aanbevole insluiting nie gelei het tot dieselfde beskikbare fosforpeile van die PC dieet nie. Verder het die insluiting van fitase tot drie keer die aanbeveling geen negatiewe uitwerking op die immuunstatus van die braaikuikens gehad nie aangesien daar geen verskille in orgaan massas en verhoudings waargeneem is nie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/96633
This item appears in the following collections: