*Dr. William A. Dudley-Cash is a poultry and fish nutritionist and has his own consulting firm in Modesto, Cal. To expedite answers to questions concerning this column, please direct inquiries to Feedstuffs, Bottom Line of Nutrition, 5810 W. 78th St., Suite 200, Bloomington, Minn. 55439, or email firstname.lastname@example.org.
NON-starch polysaccharide (NSP) enzymes are most commonly included in poultry diets containing barley and/or wheat, two feed ingredients that contain higher levels of NSPs.
NSP enzymes are not usually added to corn/soybean meal diets. However, at the International Poultry Scientific Forum, J. Klein, M. Williams and J. Lee of the Texas A&M University poultry science department, B. Brown of Enzyvia LLC, M. Kidd of the University of Arkansas and R. Brister of Tyson Foods presented abstract M60 on an experiment conducted to evaluate the inclusion of a cocktail NSP (Enspira) in low-energy corn/soybean meal diets containing dried distillers grains plus solubles (DDGS).
The experimental design consisted of three dietary treatments: (1) a positive control (PC), (2) a negative control (NC) with a reduction of 55 kcal/kg in the starter and a reduction of 88 kcal/kg in the finisher and withdrawal periods and (3) the NC supplemented with the NSP enzyme. Each treatment was fed to 16 replicate pens of 40 male broilers per replicate (1,920 total chicks).
The feeding program consisted of a starter, grower and finisher. All starter diets contained 5% DDGS, all grower diets contained 10% DDGS and all finisher diets contained 15% DDGS.
The broilers were weighed and feed consumption determined on days 14, 27 and 39. Following an eight-hour feed withdrawal, seven broilers per replicate were processed to determine carcass and fat pad yields.
When compared with the broilers fed the PC diet, bodyweights were significantly reduced on days 14 and 27 for those broilers fed the NC diet. Inclusion of the NSP enzyme significantly increased bodyweights so that the broilers fed the NC diet containing NSP enzyme had bodyweights that were similar to the broilers fed the PC diet.
Feed conversion was significantly increased for those broilers fed the NC diet compared to the PC diet during each of the feeding phases. The addition of the NSP enzyme significantly reduced the cumulative feed conversion at days 27 and 39 compared with the broilers fed the NC diet so that it was similar to feed conversion for the broilers fed the PC diet.
The carcass and fat pad yields were similar for all three treatment groups.
The Bottom Line
The authors said these data confirm that inclusion of an NSP enzyme can compensate for the loss in performance associated with reductions in dietary energy.
Amino acid density
P. Tillman of Poultry Technical Nutrition Services and K. Perryman and W. Dozier III of the Auburn University department of poultry science reported that increased dietary amino acid density from 1 to 35 days of age optimizes profitability in Hubbard M99 x Cobb 500 male broilers (abstract M61).
An experiment was conducted to determine the effects of feeding broiler diets formulated with progressive increases in digestible lysine levels on growth performance, meat yields and economic return over feed cost. In the experiment, 1,500 Hubbard M99 x Cobb 500 male chicks were randomly distributed to 16 floor pens, with 25 birds per pen (0.09 sq. m per bird at one day of age).
Five experimental diets were fed over three phases: (1) a starter for days 1-14, (2) a grower for days 15-28 and (3) a finisher for days 29-35. A low-digestible lysine basal diet and a high-digestible lysine summit diet were formulated and blended to create three additional diets.
The weighted digestible lysine concentrations were 0.88%, 0.95%, 1.02%, 1.09% and 1.16%, respectively, for the five experimental treatments. The experimental diets were formulated to all contain similar ratios of digestible threonine, sulfur amino acids, valine, isoleucine, arginine and tryptophan to digestible lysine. The authors referred to these experimental diets as basal, industry low, industry high, requirement and summit, respectively.
At 35 days of age, eight birds per pen were selected for processing.
Significant linear and quadratic increases in bodyweight gain were observed for the broilers consuming incremental concentrations of digestible lysine (and the other digestible amino acids) from day 1 to day 35 of age. These broilers also had significantly improved feed conversion when consuming higher concentrations of digestible lysine.
Incremental increases in digestible lysine concentrations resulted in a significant quadratic increase in feed intake. Those broilers that received the feeds containing a weighted average of 1.02% digestible lysine consumed the largest quantity of feed.
Significant linear increases were also observed for breast weight, breast yield, drumstick weight, wing weight and thigh weight. Significant quadratic responses were observed for drumstick weight, wing weight and thigh weight.
Return over feed cost was maximized for those broilers consuming the weighted average 1.02% digestible lysine (the industry high treatment) compared with those broilers consuming the basal diet (0.88% weighted average digestible lysine) at $3.06 versus $2.66 per bird, respectively.
The Bottom Line
These data show the importance of providing adequate dietary amino acid density to achieve optimum feed conversion, production of saleable meat and profitability.
Organic broiler diets
Sulfur amino acids are typically the first limiting amino acids in broiler diets, including organic broiler diets. Synthetic methionine has been approved for addition to organic broiler diets to meet birds' requirement for sulfur amino acids; however, the organic industry would prefer to find an organic substitute ingredient to meet the sulfur amino acid requirement.
H. Burley, P. Patterson, R. Hulet and P. Patterson of the department of animal science at The Pennsylvania State University presented research on the use of organic ingredients as a source of sulfur amino acids (abstract M65).
In experiment 1, 208 male Cobb x Ross 308 broilers were fed five diets (seven cages per diet, with eight birds per cage) from 0 to 21 days of age. The treatments consisted of a non-organic commercial control with synthetic methionine and a standard crude protein level, an organic control without synthetic methionine but with a higher crude protein level and three organic diets without synthetic methionine but with the addition of Brazil nut meal, spray-dried egg white or an egg blend of 70:30 albumen-to-yolk.
In experiment 2, 310 male Cobb x Ross 308 broilers were fed six diets (seven cages per diet, with eight birds per cage) from 0 to 21 days. The experimental treatments consisted of a non-organic commercial control with synthetic methionine and a standard crude protein level and diets containing the egg white and egg blend. Each egg diet had either low or high biotin supplementation.
The formulated methionine level was 0.51% and 0.45% for all starter and grower diets, respectively. Growth performance was monitored from 0 to 21 days, and processing yields were determined at 21 days of age.
In experiment 3, 210 male Ross x Heritage broilers were fed six diets (six cages per diet, with five birds per cage) from 31 to 35 days of age. Each of the experimental diets contained one of the experimental ingredients -- Brazil nut meal, egg white, egg blend, naked oats, hull-less barley or dehulled sunflower seed meal -- as the sole source of protein.
A protein-free diet was also fed to measure endogenous amino acid losses. Acid-insoluble ash was included as an indigestible marker in all diets. At 35 days, the ileal digesta was collected for amino acid and acid-insoluble ash analysis. Apparent and true ileal digestibility were calculated.
In experiment 1, the Brazil nut diet resulted in equivalent bodyweight gain, feed efficiency and most processing parameters to the non-organic commercial control diet. Biotin deficiency symptoms were seen for all of the egg diets in experiment 1; these deficiency symptoms were assumed to be the result of the biotin-binding egg white protein avidin present in the egg products.
These symptoms were eliminated in experiment 2 by the addition of dietary biotin. The egg diets also resulted in reduced growth and feed efficiency and processing weights compared with the non-organic commercial control diet. Bodyweight gain averaged 696 g for the control diet compared to an average of 597 g for the egg diets.
The egg diets and Brazil nut diets had a lower cost per ton and cost per kilogram of bled breast and sum of parts weights compared with the organic control diet.
In experiment 3, the egg white diet had lower apparent and true digestibility compared with the naked oats and sunflower seed meal.
The Bottom Line
These results show that Brazil nut meal can be used to replace synthetic methionine and maintain broiler growth in organic broiler diets. The depressed bird growth and feed intake caused by egg products in this study indicates that these spray-dried products are probably not suitable for feeding broilers in their current form.
Medium-chain fatty acids
K. Deschepper, R. Goedegebuure and R. Costa of Nuscience in Belgium and L. Maertens of ILVO in Belgium presented a paper (abstract M68) on the effect of adding a balanced mixture of medium-chain fatty acids (MCFA) to broiler feed on growth performance and processing yield.
Two experiments were conducted with male Ross 308 broilers using a three-phase feeding program with 13 days for each phase.
Experiment 1 consisted of two dietary treatments -- control and MCFA (Aromabiotic Poultry) -- with nine replicates of 32 birds per replicate for each treatment for a total of 576 birds. The basal diet was a wheat/corn/soybean meal diet. MCFA was added at a level of 1.70, 1.25 and 0.80 g/kg to the starter, grower and finisher, respectively.
Experiment 2 consisted of three dietary treatments with seven replicates of 30 birds per treatment for a total of 630 birds fed starter, grower and finisher diets over 39 days. The three treatments consisted of a wheat/corn/soybean meal control diet and the control diet with the addition of either 0.8 or 1.2 g/kg of MCFA.
For each experiment, the average pen weight was recorded at 13, 26 and 39 days of age. Feed intake was recorded for days 1-13, 14-26 and 27-39. At the end of the second experiment, two broilers of average pen weight were selected from each pen for the determination of processing results.
In experiment 1, the addition of MCFA significantly improved average daily gain in the starter, grower and overall: 67.6 g versus 64.6 g per day. After correcting for weight differences, feed conversion was two points better for the group receiving MCFA compared to the control group: 1.62 versus 1.64.
In experiment 2, average daily gain and feed conversion were significantly improved by the addition of MCFA. The best results were observed with the lower level of MCFA: 64.9 g versus 62.6 g per day for gain and 1.53 versus 1.58 for feed conversion. Breast meat yield was improved only at the higher dosage of MCFA: 23.1% versus 22.6%.
The Bottom Line
An MCFA mixture is a functional feed ingredient that was found to improve broiler performance in this research.
The abstracts of the International Poultry Scientific Forum may be found on the U.S. Poultry & Egg Assn. website at www.ipe13.org/ipsf/docs/13AbstractBook.pdf.