Effects of phytase inclusions in diets containing ground wheat or 12.5% whole wheat (pre- and post-pellet) and phytase and protease additions, individually and in combination, to diets containing 12.5% pre-pellet whole wheat on the performance of broiler chickens

Use of wheat dilution to improve digestive function in broilers: application in low protein diets

1. This study evaluated the effect of wheat dilution increasing in particle size in low crude protein diets on growth performance, digestive tract, nitrogen efficiency and litter quality in broiler chickens.2. Ross 308 male broiler chicks (n = 336) were allocated to one of four dietary treatments (each with 7 pens, 12 chicks per pen); Control (CON; commercial pellet diet with standard crude protein, CP: 22.50%), W578 (CON +20% wheat of geometric mean diameter (GMD) of 578 µm; CP: 20.25%), W1326 (CON +20% wheat of GMD 1326 µm; CP: 20.25%) and WW (CON +20% whole wheat, CP: 20.25%), from d 0 to 21 of age.3. Body weight gain was increased (P < 0.05) for birds fed CON compared to the low crude protein diets. However, WW increased (P < 0.05) body weight gain compared to W578 and W1326, while feed intake and feed conversion ratio on CON and WW were similar (P > 0.05). Birds fed W1326 showed the poorest (P < 0.05) FCR compared to CON, W578 and WW.4. Gizzard relative weight (g/kg body weight) was increased (P < 0.05) on WW compared to CON on d 14 and 21, whereas gastric isthmus diameter was significantly reduced on W1326 and WW compared with CON and W578.5. There were no differences (P > 0.05) in the depth of gizzard mucosa of lamina propria between CON and WW at d 14 and 21. Birds fed WW increased (P < 0.05) gizzard tensile strength compared to W578 and W1326, whereas no difference was observed between WW and CON on d 14.6. No significant differences were seen for ileum villus height and mucosal layer between CON and WW on d 21, however, feeding CON increased the extent of the mucosal layer compared to W578 and W1326.7. Nitrogen excretion (g/kg BWG) was significantly lower (P > 0.05) on W1326 and WW compared with CON and W578. Litter nitrogen, moisture, and footpad scores significantly decreased (P < 0.05) for birds fed WW compared with CON.8. Diluting dietary protein content from 22.50 to 20.25% resulted in lower body weight gain in broilers. However, dilution with whole wheat resulted in comparable FCR, reduced nitrogen excretion, litter moisture and footpad dermatitis compared with a standard protein diet.

Growth performance and nutrient digestibility of broiler chickens as affected by a novel protease

Two experiments evaluated the addition of an exogenous sfericase protease in broiler diets. Experiments were run (Exp1 and Exp2) with 1,848 and 2,100 one-day-old male chicks being allocated into 84 floor pens with 14 replicates of 22 and 25 birds each, respectively. The studies were conducted in completely randomized designs. In Exp1, Standard diets were formulated with energy and AA at marginally lower levels than usual by the Brazilian integration such that broilers were expected to grow at comparatively reduced rates to the industry whereas in Exp2, the Standard diets were formulated using energy and AA as usual by the Brazilian integrations such that broilers were expected to grow comparable to industry rates. Standard diets had ideally balanced amino acids (AA). Matrix diets, in contrast, had reductions of 6% digestible lysine and of 20 kcal AME/kg compared to the Standard. Matrix diets were supplemented with an sfericase protease at 0, 10,000, and 30,000 New Feed Protease units (NFP)/kg. Outcomes showed no interaction between diet and protease in any of the experiments. However, broilers fed Standard diets had higher cumulative body weight gain (BWG) to 35 and 42 d when compared to Matrix fed birds whereas FCR were worse for birds fed the Matrix diets at 35 d in EXP1 and at 35 and 42 d in EXP2. Improvements in FCR were observed when the sfericase protease was added throughout all ages in EXP1 with a beneficial trend (P&lt;0.067) observed in the cumulative FCR at 42 d in EXP2. The ileal digestible crude protein (IDCP) was significantly higher for birds fed Standard feeds in EXP1 with no other differences in digestibility found in any of the experiments. Protease addition led to improvements in ileal digestibility of dry matter (IDM) and IDCP (P &lt; 0.05) compared to no protease addition in EXP1 as well as in ileal digestibility of energy (IDE) when 30,000 protease units were added. The present report demonstrates that the novel sfericase protease was successful in compensate broiler performance when reductions of 6% digestible Lys and 20 kcal/kg AME were imposed. This compensation, however, seemed more notable when birds were fed diets formulated to support moderate rather than maximum growth and having animal protein in the feed formula.

The influence of phytase, pre-pellet cracked maize and dietary crude protein level on broiler performance via response surface methodology

Background

The reduction of crude protein levels in diets for broiler chickens may generate economic, environmental and flock welfare and health benefits; however, performance is usually compromised. Whole grain feeding and phytase may improve the utilization of reduced crude protein diets.

Results

The effects of pre-pellet cracked maize (0, 15% and 30%) and phytase (0, 750 and 1500 FTU/kg) in iso-energetic maize-soy diets with three levels of crude protein (22%, 19.5% and 17%) were evaluated via a Box-Behnken response surface design. Each of 13 dietary treatments were offered to 6 replicate cages (6 birds/cage) of male Ross 308 broiler chicks from 7 to 28 d post-hatch. Model prediction and response surface plots were generated from experimental data via polynomial regression in R and only significant coefficients were included and discussed in the predicted models. Weight gain, feed intake and FCR were all influenced by pre-pellet cracked maize, phytase and crude protein level, where crude protein level had the greatest influence. Consequently, the reduction from 22% to 17% dietary crude protein in non-supplemented diets reduced weight gain, feed intake, relative gizzard weight, relative gizzard content and relative pancreas weight but improved FCR. However, the inclusion of 30% cracked maize to 17% crude protein diets restored gizzard weight and 1500 FTU phytase inclusion to 17% crude protein diets increased relative gizzard contents and pancreas weights. Cracked maize and phytase inclusion in tandem to 17% crude protein diets increased weight gain, feed intake and FCR; however, this FCR was still more efficient than broilers offered the non-supplemented 22% crude protein diet. Broilers offered the pre-pellet cracked maize and phytase inclusions reduced AME in 22% crude protein diets but improved AME by 2.92 MJ (14.16 versus 11.24 MJ; P < 0.001) in diets containing 17% crude protein. Ileal N digestibility was greater in broilers offered diets with 17% crude protein than those offered the 22% crude protein diet; irrespective of phytase and pre-pellet cracked maize.

Conclusion

Pre-pellet cracked maize and phytase inclusions will improve the performance of broilers offered reduced crude protein diets.

Feeding whole grain and phytase to meat chickens: recent Australian experience

Both whole-grain feeding and exogenous phytases have been widely accepted by the chicken-meat industry, so any interactions that arise from this combined supplementation are potentially important. Nevertheless, there is a paucity of research evaluating the effect of phytase under whole-grain feeding regimens. Whole-grain feeding increases relative gizzard weights and gizzard functionality. However, the gizzard is the primary site of phytate degradation by phytase, so this combined supplementation should enhance phytase efficacy. Moreover, there has been recent progress towards understanding the influence of whole-grain feeding and exogenous phytase on broiler performance, which is discussed. Further research is warranted to establish a whole-grain feeding regimen that generates robust gizzard responses so as to enhance feed efficiency, energy utilisation and phytase efficacy.

Current and Future Applications of Phytases in Poultry Industry: A Critical Review

Phytases are enzymes that initiate the removal of phosphate from phytate. This enzyme has been widely utilized in animal feeding especially in the poultry industry to enhance phosphorus intake and minimize environmental pollution. Phytases are widely distributed in microbial, plants and animals. Supplementations of phytase into the diets of poultry have great impact to the improvement of poultry immune systems and increase bird weight. In addition to that, phytase are able to improve both quantity and quality of eggs, egg mass and egg shell quality. This review covers the classifications and distribution of phytases in different biofactoris. In addition, it shed more light on the recent trends of application and beneficial impact in poultry farming.

Progress in comprehending the phytate–phytase axis in chicken-meat production

After an extended delay, the level of acceptance of exogenous phytases by the global chicken-meat industry is now almost complete. Contemporary bacterial phytases degrade phytate primarily in the gizzard. The extent of phytate degradation determines the extent to which phytate-bound phosphorus (P) is liberated; however, studies designed to investigate phytate degradation along the digestive tract have generated some confusing outcomes. This may be related to the reactivity of the phytate moiety, coupled with problems with inert dietary markers and perhaps a lack of complete and uniform extractions of phytate from digesta due to variations in digesta pH and phytate solubility. Quite recently, phytase was shown to have profound impacts on sodium (Na) digestibility coefficients in four segments of the small intestine. This has obvious implications for intestinal uptakes of glucose and amino acids via their respective Na+-dependent transport systems and it is possible that phytate and phytase have reciprocal impacts on ‘sodium pump’ (Na+, K+-ATPase) activity. It has been recently demonstrated unequivocally that phytase has the capacity to increase amino acid digestibility coefficients to the extent that phytase may generate a ‘proximal shift’ in the sites of amino acid absorption. The impact of phytase on starch digestibility is more equivocal and phytase responses may stem more from enhanced glucose absorption rather than starch digestion. The acceptance of phytase is hardly surprising, given its capacity to increase P utilisation coupled with numerous other positive influences that are still being properly realised.