Measurements of enzyme response with hulless barley-based diets full-fed to Leghorn and broiler chicks or restricted-fed broiler chicks

Abstract

A, 2001. Measurements of enzyme response with hulless barley-based diets full-fed to Leghorn and broiler chicks or restricted-fed broiler chicks. Can J. Anim. Sci. 81: 403-410. Broiler chicks fed diets high in soluble non-starch polysaccharides (NSP; e.g., wheat-and/or barley-based diets) have a higher capacity to ingest, digest and absorb nutrients when diets are supplemented with appropriate NSP enzymes. However, this same enzyme response is typically reduced or non-significant in older birds, Leghorn chicks and turkey poults. We hypothesise that the enzyme response in the latter classes of poultry is reduced because feed intake is lower in comparison to feed intake by broilers. In the present study, the hypothesis that restricted feeding of broilers would reduce the enzyme response typically observed in full-fed broilers was tested.Two experiments were conducted to determine the feeding value of hulless barley supplemented or not supplemented with enzyme (Avizyme 1100, Finnfeeds Int, UK). In Study 1, eight sources of hulless barley were included at 80% in each diet and fed to four groups of six male broilers or Leghorn chicks from 4 to 17 d of age. The response to enzyme in hulless barley-based diets by broilers was approximately twofold that of Leghorns for growth and feed intake. The Leghorns had higher digesta viscosity than broilers, although the relative drop in digesta viscosity with enzyme supplementation was equal.In a second study (Study 2) broiler chicks were fed one of four diets (two hulless barley cultivars with or without enzyme) at three feed allotment levels (ad libitum, R1 and R2) from 4 to 21 d of age. The R1 and R2 feed allotments were pre-determined fixed daily feed amounts. Actual feed restriction in the R1 group was only achieved for diets with, but not without, an enzyme. At the lowest feed allotment (R2) actual feed intake of diets with or without enzyme were lower than that recorded for ad libitum fed birds. Study 2 demonstrated that restricted-fed broilers had a lower growth response to enzyme supplementation compared to birds allowed ad libitum intake, in part due to improved retention of energy, either directly in response to feed restriction or because digesta viscosity in diets without enzyme was lowered. Although digesta viscosity of restricted-fed birds was lower, it is still high enough to be considered problematic. In determining feeding value of cereal grains or supplements such as enzymes, especially those directed for use with broilers, it is imperative that a broiler chick bioassay be used and that they have ad libitum access to the diets. Les poussins de chair qui reçoivent une ration riche en polysaccharides solubles autres que l'amidon (par ex., une ration à base de blé et/ou d'orge) ingèrent, digèrent et assimilent mieux les éléments nutritifs quand on ajoute les enzymes appropriés à la nourriture. Toutefois, l'activité des enzymes diminue ou devient insignifiante chez les oiseaux plus âgés, chez les poussins Leghorn et chez les dindonneaux. Les auteurs présument que...

Avaliação De Programas Nutricionais Com a Utilização De Carboidrases E Fitase Em Rações De Frangos De Corte

“…A suplementação do complexo enzimático pode ter promovido melhor digestibilidade dos nutrientes presentes nas dietas, degradando os complexos de fibras solúveis, reduzindo a viscosidade da digesta através da degradação das arabinoxilanas solúveis das paredes celulares dos grãos, ocasionando melhor digestibilidade dos demais nutrientes. SCOTT et al (2001), ao estudarem a suplementação de enzimas em frangos de corte alimentados ad libitum ou de forma restrita, também verificaram maior consumo de ração para os tratamentos suplementados com β-glucanase e que a resposta à suplementação de enzimas está relacionada diretamente ao consumo voluntário de ração. SORBARA et al (2009) avaliaram a inclusão de α-amilase, β-glucanase e xilanase durante a fase crescimento de frangos de corte e concluíram que a suplementação enzimática pode melhorar a capacidade digestiva das aves por aumentar a digestão dos nutrientes, resultando em maior absorção e maior consumo de ração e, consequentemente, em maior ganho de peso.…”

Organic poultry production and forage digestibility

“…However, Scott et al reported an enzyme effect only when broiler chicks were restricted to 80% and 60% intake. Restricted fed birds had similar AME values compared to ad libitum fed birds when supplemented with a NSP enzyme; however, restricted-fed birds were not able to overcome nutrient deficiencies when diets were not supplemented with a NSP enzyme [43]. The authors contribute this finding to an increase in a restricted-fed bird's ability to digest the feedstuff and attain higher growth.…”

“…However, roosters precision-fed the LOW/E had similar AME n and TME n values compared to roosters precision-fed NOR/NE and higher AME n and TME n values compared to roosters precision-fed LOW/NE (P=0.0001). The variation in enzyme effect between normal energy diets and low energy diets is supported by Kocher [42] and Scott [43]. Kocher reported no significant enzyme effect in AME when broiler chickens were fed a nutritionally adequate lupin-based diet [42].…”

“…Supplementing broiler diets with high levels of fat may significantly lengthen feed passage time for broiler chickens [42,43,44]. Additionally, variation in particle size and feed restriction may also affect the rate of feed passage in poultry.…”