In vivo dry matter and protein digestibility of three plant-derived and four animal-derived feedstuffs and diets for juvenile Australian redclaw, Cherax quadricarinatus

Abstract

Dry matter and protein digestibility of three plant-derived and four animal-derived feedstuffs and diets in which they were included were evaluated for juvenile Australian redclaw. The ingredients evaluated were: soy paste, textured wheat, sorghum meal, two sardine meals (67% and 58% crude protein), squid meal, and red crab meal. A reference diet was formulated and produced in the CIBNOR nutrition laboratory. Seven experimental diets were then made including 15% of each ingredient in the reference diet. The experiment consists of a single-factor, completely randomized design with five replicates per treatment. Digestibility was measured indirectly, using chromic oxide as a marker. Plant-derived ingredients and the corresponding diets had, in general, a higher digestibility than animal ingredients. Soy paste and sorghum meals, and the diets in which they were included, showed an excellent dry matter (over 87%) and protein (approximately 90%) digestibility. Some of the animal ingredients such as sardine meal 67% CP and squid meal had a good dry matter digestibility (over 80%), but were significantly lower than plant-derived ingredients. The lowest dry matter and protein digestibility was recorded for sardine meal 58% CP and red crab meal. It is concluded that juvenile redclaw are omnivorous and able to efficiently consume diets containing plant- and animal-derived ingredients, but they can digest plant-derived ingredients more efficiently.