Fish Viscera Silage as a Protein Source for Poultry

Abstract

Fish viscera silage was evaluated as a protein source for chicks and hens on the basis of content and digestibility of amino acids and nitrogen, effects on growth and meat quality in chicks, and effects on egg production and egg and meat quality in hens. The experiments comprised several viscera products; fresh, acid preserved, ensiled, and ensiled concentrated viscera. Acid preservation and ensiling did not affect the content of most amino acids and the amino acids were highly digestible. The tryptophan content was, however, reduced and the digestibility of this amino acid was low. Viscera products constituted up to 40% of protein in chick diets. Chicks fed viscera diets performed as good as, or better, than chicks fed the control diets. A low fat content of the viscera products seemed to be a prerequisite for good quality of chick meat. Egg production and feed efficiency were not affected by diets containing 20% of protein from concentrated viscera silage. Hens fed 40% of the protein from silage showed a significantly inferior energy and nitrogen utilization, possibly due to a deficiency of sulphur-containing amino acids. These effects did not appear to be caused by toxic compounds in the viscera silage. No important differences in quality of eggs from hens fed different diets were found. Viscera fat did not affect the sensory quality of eggs importantly, neither the quality of the meat from the hens.

Key Words:

• Digestibility
• growth
• egg production
• product qualities