*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 [email protected]
THE 102nd annual meeting of the Poultry Science Assn. was held July 22-25 in San Diego, Cal., with a total of 930 registrants plus an additional 70 guests.
More than half of the attendees were from the U.S., but double-digit numbers were also present from Brazil, Canada, Mexico, China, Thailand, Japan and the U.K. In all, 45 countries were represented.
A part of the large turnout could be attributed to the well-known San Diego climate and the abundance of local attractions, but the fact that most chicken companies are experiencing record profits was clearly a contributor to the attendance. An outstanding technical program was a major attraction as well.
There were 504 papers presented, either orally or as posters, in sections devoted to topics on: environment and management; feed additives; nutrition; physiology, endocrinology and reproduction; processing, products and food safety; behavior and well-being; enzymes; vitamins and minerals; extension and instruction; genetics; immunology; pathology, and amino acids.
There were also 12 symposia, workshops and keynote addresses.
An important addition to the program this year was the use of simultaneous English to Spanish translation in some of the sessions. This feature was well received, and the program committee is planning to expand the use of English to Spanish translation at the next annual meeting.
The abstracts for the meeting may be found at the association's website at www.poultryscience.org under the "Meetings" tab. The list of award recipients is also posted on the website.
Ingredient prices are still high enough to focus attention on the development of alternative ingredients that have the potential to replace expensive corn and soybean meal. Several papers on alternative ingredients were presented at the meeting this year.
J. Price et al. of the Texas A&M University departments of poultry science and animal science reported on an evaluation of a post-extraction algal residue as a feed ingredient in broiler and laying hen diets (abstract P416).
The algal residue was determined to contain 20.2% crude protein, 6.18% calcium, 6.61% sodium and 1.56% fat. A complete amino acid, vitamin and mineral analysis was conducted before diet formulation.
In experiment 1, increasing concentrations (0%, 5%, 10%, 15% and 20%) of algal residue were included in 31-week-old White Leghorn laying hen diets. The hens were fed the diets for a period of five weeks. During the experiment, weekly feed consumption, egg production, egg weight and interior egg quality were measured.
Increasing concentrations of algal residue had no effect on egg production or feed consumption. However, yolk color increased from feeding 10% algal residue after two weeks of consumption.
In experiment 2, increasing concentrations (0%, 2.5%, 5.0%, 7.5% and 10.0%) of algal residue were fed to broilers through three weeks of age. The inclusion of algal residue did not affect feed consumption, bodyweight or feed conversion throughout the three-week experiment. However, an increase in fecal moisture was observed with the 7.5% and 10.0% dietary treatments.
The Bottom Line
These data indicate that algal residue can be included in poultry diets without having negative effects on performance.
Sweet potato root
The influence of replacing different levels of corn with sweet potato root meal (SPRM) on the performance and meat quality of broilers was reported by R. Beckford et al. of Tuskegee University.
After a complete nutrient analysis of SPRM, diets were formulated to contain 0%, 10%, 20% and 30% SPRM, which was substituted for corn. The study randomly assigned 360 one-day-old Cornish rock male broilers to the four treatments. Bodyweights and feed intake were measured weekly for seven weeks. Birds were slaughtered at 50 days of age.
Results showed no significant differences among treatments for feed intake, average daily gain and feed efficiency. Birds fed the 30% level of SPRM had significantly higher bodyweight gain and average daily gain compared with the birds fed 20% SPRM.
There were no significant differences among treatments in dressing percentage or organ weights. Abdominal fat content was highest in those birds fed 30% SPRM.
The moisture, protein and ash contents of the white meat were not significantly different among treatments, while fat content was significantly lower for birds fed the 0% SPRM control diet. For dark meat, protein and ash contents were similar among all treatments, while moisture and fat contents were significantly different.
The Bottom Line
Birds fed SPRM diets compared well with those fed the control diet for both performance and the nutrient content of meat.
The effect of feeding a single-cell protein produced from date waste on the performance of laying hens was reported by H. Najib and S. Hamad of the King Faisal University College of Agriculture & Food Sciences, S. Aleid of the King Faisal University Date Palm Research Center of Excellence and F. Al-Jasass of the King Abdulaziz City of Science & Technology, General Directorate of Research Grants, Saudi Arabia (abstract 232).
An experiment was conducted using increasing levels (0%, 5%, 10% and 15%) of a single-cell protein yeast in the diet of laying hens.
An intensive chemical analysis and true metabolizable energy determination were performed on the yeast. Based on these analyses, iso-nitrogenous, iso-caloric layer diets were formulated to feed to 35-week-old layers. Sixty layers were distributed in 12 cages of five birds per cage. The treatments were then distributed among the cages. The experiment continued for 24 weeks.
The results of the analysis of the yeast showed that true metabolizable energy was about 3,380 kcal/kg, while the protein content was 48%. The protein was found to be rich in lysine (1.02%). The level of fat in the yeast was only 6.41%; however, oleic acid made up 43.2% of the total fat.
Hen-day egg production, egg mass, egg weight and feed conversion were significantly better when 5% yeast was included in the ration. However, there was a clear indication that the addition of 15% yeast may be harmful to the birds.
The Bottom Line
The researchers concluded that adding 5% of a single-cell yeast protein product to the diet produced no adverse effect on the performance of laying hens.
M. Oryschak of Alberta Agriculture & Rural Development and E. Beltranena of Alberta Agriculture & Rural Development and the University of Alberta reported on an evaluation of expeller-pressed Camelina sativa meal (CAM) as a feedstuff for layers.
Analysis values of CAM were 32.6% crude protein, 11.5% fat and 35.6 micromoles per gram of total glucosinolates.
In abstract P420, the researchers reported on the effects of increasing dietary inclusion of CAM and layer strain on feed intake, egg production and physical egg quality. The experimental treatments consisted of 0%, 5%, 10%, 15%, 20% or 25% dietary inclusion levels of CAM fed to brown- and white-strain H&N hens in a 2 x 6 factorial arrangement for a total of 12 treatments. Each treatment was applied to six replicate cages of four hens per cage for a total of 288 hens (144 brown and 144 white).
Phase 1 diets (22-46 weeks of age) were formulated to contain 2.8 megacalories of apparent metabolizable energy (AME) per kilogram, 3.70% calcium, 0.43% available phosphorus, 2.4 g of apparent ileal digestible lysine per megacalorie of AME and other apparent ileal digestible amino acids in recommended ratios to lysine.
There was no interaction between strain and dietary treatment for any performance or egg quality variables. For the overall 24-week study, average daily feed intake was significantly lower for the 25% CAM diet compared with all other CAM levels. Laying percentage was significantly higher for the 5% and 10% CAM levels compared with all other diets. As CAM inclusion increased, there was a significant linear reduction in average egg weight and daily egg mass production, which was attributable to a linear reduction in albumin weight.
There was no effect of CAM inclusion on any other objective measure of egg quality or weight of egg components.
The researchers concluded that the results of this experiment indicate that increasing the CAM level of the diet did not result in feed refusal and supported acceptable laying hen productivity. More accurate nutrient digestibility coefficients are necessary to optimize the use of CAM in laying hen diets.
In a companion paper (abstract 227), the researchers reported the results of an experiment designed to determine the effects of increasing dietary inclusion of CAM and copper supplementation on egg production and physical egg quality.
The experimental design was very similar to the experiment reported in abstract P420 but still differed. The basal diet and the experimental period were the same (22-46 weeks). CAM had the same analysis, and the inclusion levels of CAM were the same. Each level of CAM was fed with and without 125 parts per million of supplemental copper in a 2 x 6 factorial arrangement for a total of 12 treatments. Each of the 12 treatments were fed to six replicate cages of four brown H&N hens per cage.
For the overall 24-week study, increasing dietary CAM inclusion linearly reduced average daily feed intake, feed efficiency and laying percentage (P < 0.01). Increasing CAM inclusion also linearly reduced average egg weight and daily egg mass (P < 0.01), which was attributable to a linear decrease in albumin weight. Supplemental copper significantly increased average daily feed intake, average egg weight and daily egg mass production but slightly reduced laying percentage.
The researchers concluded that the results of this experiment indicate that there was a reduction in AME and digestible amino acids with increasing CAM inclusion in the diet.
A follow-on paper (abstract P421) reported on any signs of toxicity, effects on organ weights and serology in hens from the research reported in abstracts P420 and 227 (the same authors plus C. Christianson of Alberta Agriculture & Rural Development).
After nine weeks on test, a single bird was randomly selected from each test cage to obtain a blood sample, after which the bird was euthanized. Birds were sent for postmortem examination by a veterinary pathologist to look for signs of CAM or copper toxicity and to measure the weights of key organs. Postmortem examination of tissue morphology (including the thyroid) did not suggest toxicity of either CAM or copper supplementation.
Pancreas weight (as a percentage of total bodyweight) significantly increased with increasing CAM inclusion in both experiments. Plasma T3 concentrations in the 25% CAM diets were significantly lower than the other diets only in the hens from abstract P420. Other than a small increase in heart weight as a percentage of bodyweight (P < 0.01), dietary copper supplementation had no effect on any other variables.
The Bottom Line
The researchers concluded that the dietary inclusion of CAM at up to 25%, with or without copper supplementation, did not result in evidence of toxicity in laying hens.