The use of fibrolytic enzymes in maize-soya based broiler diets

Botha, Corne J. (2011-03)

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011.

Includes bibliography.

Thesis

ENGLISH ABSTRACT: A growth and digestibility trial was conducted comparing the effect of an experimental enzyme at three different inclusions. A negative control containing no enzyme additions and a positive control containing a proven commercial enzyme were compared in a maize-soybean diet noting the performance of broilers and the digestibility of the grower feed. The commercial enzyme was a granular product with a xylanase activity of 38114.29 nkat/g and the second enzyme (ABO374) was a liquid experimental product with a xylanase activity of 1426.86 nkat/ml. Five diets were used i.e. control basal diet without enzyme supplementation (negative control), basal diet supplemented with the commercial enzyme (positive control) and three basal diets supplemented with the test enzyme at various inclusion levels (ABO 50, ABO 100 and ABO 200). The positive control was supplemented with 200 g/ton of the commercial enzyme; ABO 50 was supplemented with ABO374 at an inclusion level of 2671 ml/ton, ABO 100 with 5342 ml/ton and ABO 200 with 10684 ml/ton. Supplementation with the test enzyme (ABO 50) significantly improved BW at 23 days of age by 4.6 % (1107.4 g vs 960.96 g) and at 37 days of age by 3.2 % (2311.75 g vs 2237.81 g) over the negative control. Body weight gain for the total period of the trial was significantly improved by 3.24 % (64.32 g/bird/day vs 62.24 g/bird/day) the test enzyme supplementation (ABO 50) when compared to the negative control. During the starter phase, test enzyme supplementation (ABO 50) led to an improvement of 4.58 % (1.25 vs 1.31) in FCR in comparison with the negative control. The FCR for the total trial obtained by the test enzyme supplementation was significantly lower than the FCR obtained by the positive control. The highest EPER obtained for this trail was by the test enzyme supplemented diets and this was significantly higher than the EPER obtained by the positive control. It is clear from this growth trial that the test enzyme (ABO374) at an inclusion level of 2671 ml/ton outperformed the commercial enzyme and that it has the potential to improve the production performance of broilers on a maizeSBM based diet. The total tract digestibility method and total collection method was used to conduct the digestibility trial. The total tract digestibility method measures the difference between the amounts of each nutrient consumed from the amounts of each nutrient excreted in faeces. Only apparent digestibilities are reported for the digestibility trial. Apparent digestibility does not take the endogenous protein fraction in the faeces into account. The endogenous protein fraction is derived from digestive enzymes and proteins from the intestinal walls that are secreted into the digestive tract. The grower negative control, positive control, ABO 50, ABO 100 and ABO 200 diets used in the production trial were also used in the digestibility trial. Supplementation with the test enzyme showed no significant improvements on the apparent digestibility of dry matter, organic material, ash, crude protein, metabolisable energy or crude fibre. No significant improvements in the apparent digestibility of the amino acids (threonine, arginine, valine, lysine, methionine, cysteine and isoleucine) were noticed either and thus the digestibility of the grower feed were not influenced by the addition of enzymes due to the supplementation of the test enzyme ABO374. Pelletisation of the grower diets could have lead to the inactivation of the enzyme due to the high temperature at which pelletisation takes place. Another possible reason why enzyme supplementation did not increase nutrient digestibility, may be that the breakdown of non-starch polysaccharides by the enzymes led to an increase in the concentration of oligosaccharides in the small intestine of the birds, thus leading to the decrease in nutrient absorption Key words: body weight, body weight gain, feed conversion ratio, European production efficiency ratio, maize, soybean meal, apparent digestibility, dry matter, organic material, ash, crude protein, metabolisable energy, crude fibre, xylanase, pellitisation.

AFRIKAANSE OPSOMMING: ‘n Groei en vertering studie was uitgevoer om die effek van ‘n eksperimentele ensiem wat teen drie verskillende insluitingsvlakke by ‘n basale dieët bygevoeg is te vergelyk met ‘n negatiewe kontrole wat geen ensiem bevat het nie en met ‘n positiewe kontrole wat ‘n kommersiële ensiem bevat in ‘n mielesojaboon oliekoek dieët op die produksie vermoë van braaikuikens en die verteerbaarheid van die groei voer. Die kommersiële ensiem was ‘n granulêre produk met ‘n xylanase aktiwiteit van 38114.29 nkat/g en die eksperimentele ensiem (ABO374) was ‘n vloeistof produk met ‘n xylanase aktiwiteit van 1426.86 nkat/ml. Vyf diëte was gebruik nl. ‘n basale dieët met geen ensiem byvoeging (negatiewe kontrole), basale dieët met die byvoeging van die kommersiële ensiem (positiewe kontrole) en drie basale diëte wat met die byvoeging van die eksperimentele ensiem teen drie verskillende insluitings vlakke (ABO 50, ABO 100 and ABO 200). Die kommersiële ensiem was by die positiewe kontrole bygevoeg met ‘n insluitings vlak van 200 g/ton, ABO374 was bygevoeg by ABO 50 met ‘n insluitings vlak van 2671 ml/ton, ABO 100 met 5342 ml/ton en ABO 200 met 10684 ml/ton. Die byvoeging van die eksperimentele ensiem (ABO 50) het gelei tot die betekenisvolle verbetering van die liggaamsmassa van die voëls by die ouderdom van 23 dae met 4.6 % (1107.4 g teenoor 960.96 g) en by die ouderdom van 37 dae met 3.2 % (2311.75 g teenoor 2237.81 g) teenoor die negatiewe kontrole. Liggaams massa toename vir die hele periode van die studie was betekenisvol verhoog met 3.24 % (64.32 g/kuiken/dag teenoor 62.24 g/kuilen/dag) met die byvoeging van die eksperimentele ensiem (ABO374) teenoor die negatiewe kontrole. Voeromset verhouding was betekenisvol verbeter met 4.58 % (1.25 teenoor 1.31) toe die kommersiële ensiem bygevoeg was teenoor die negatiewe kontrole. Die hoogste europese produksie effektiwiteits verhouding wat verkry is vir die hele studie periode is deur die byvoeging van die eksperimentele ensiem (ABO374). Hierdie groei studie dui dus duidelik aan dat die gebruik van die eksperimentele ensiem (ABO374) baie beter resultate as die kommersiële ensiem opgelewer het teen ‘n insluitings vlak van 2671 ml/ton, dus het ABO374 die potensiaal om die produksie potensiaal van braaikuikens op ‘n mielie-sojaboonoliekoek dieët te verbeter. Die totale spysverteringskanaal verteerbaarheid metode was gebruik om die verteerbaarheid studie uit te voer. Die totale spysverteringskanaal verteerbaarheid metode meet die verskil tussen die nutriënt inhoud van die voer en die nutriënt inhoud van die mis. Slegs die skynbare verteerbaarheid van nutriënte word vir hierdie verteerbaarheidstudie gerapporteer. Skynbare verteerbaarheid sluit nie die endogene proteïenfraksie wat afkomstig is van verteringsensieme of die proteïene afkomstig vanaf die spysverteringskanaal se intestinale wande af in nie. Die negatiewe kontrole, positiewe kontrole, ABO 50, ABO 100 en ABO 200 groei diëte gebruik in die produksie studie is gebruik vir die verteringsstudie. Die byvoeging van die eksperimentele ensiem het geen betekenisvolle resultate opgelewer ten opsigte van droë materiaal, organiese material, as, ru-proteïen, ru-vesel of metaboliseerbare energie nie. Daar was ook geen betekenisvolle resultate opgelewer wanneer die eksperimentele ensiem bygevoeg was nie ten opsigte van die verteerbaarheid vir aminosure (treonien, arginien, valien, metionien, sisteïen en isoleosien) nie en dus is die verteerbaarheid van die groeivoer glad nie beïnvloed deur die byvoeging van die eksperimentele ensiem nie. Die verpilling van die groei voer mag dalk gelei het tot die inaktivering van die eksperimentele ensiem deur dat dit blootgestel was aan hoë temperature. ‘n Ander moontlike rede vir die mislukking van die ensiem kon gewees het dat die afbreking van die nie-stysel polisakkariedes deur die ensiem kon gelei het tot die verhoging van die oligosakkariede konsentrasie in die laer spysverterings kanaal en dus kon dit lei tot ‘n verhoogde deurvloeitempo, gevolg deur ‘n afname in die absorpsie van nutriënte. Sleutel woorde: Liggaamsmassa, liggaamsmassa toename, voeromsetverhouding Europese produksie effektiwiteits verhouding, mielie, sojaboonoliekoek, skynbare verteerbaarheid, droëmaterial, organiesematerial, as, ru-proteïen, ru-vesel, metaboliseerbare energie, verpilling.

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