Digestibility by mink and storage stability of feedstuffs made from raw ground, acid-treated or fermented dogfish (Squalus acanthias)

Abstract

White, M. B., Anderson, D. M. and Rouvinen, K. I. 1998. Digestibility by mink and storage stability of feedstuffs made from raw ground, acid-treated or fermented dogfish (Squalus acanthias). Can. J. Anim. Sci. 78: 633-640. Dogfish was evaluated in a 3 × 4 factorial design experiment conducted to determine digestibility coefficients (DC) of dry matter (DM), crude protein (CP), crude fat (CF), gross energy (GE) and amino acids (AA) in raw ground dogfish (RGD), acid (ASD) and fermented (FSD) dogfish silages for mink. The ASD was prepared with the addition of 2.5% (wt:wt) formic acid (conc. 85%) and 200 mg kg -1 antioxidant (ethoxyquin) to the raw ground fish. The FSD was produced with the addition of the commercial biopreservative Marisil ® , (Finn Sugar) (1%) and extruded wheat (15%) to the raw ground fish. In the digestibility trial, consisting of three, 11-d periods, each having a 6-d adjustment followed by a 5-d collection, 12 mature standard type mink were confined to metabolism cages. Using the total collection (TC) method, where graded levels (0, 15, 30 and 45%) of the test feedstuff were substituted into a basal diet, an extrapolation using regression analysis was done to estimate digestibility of each test feedstuff. The AD of DM, CP, CF and GE was RGD: 81.8, 92.2, 96.2 and 89.6%; ASD: 87.1, 92.6, 100.0 and 93.2%; FSD: 86.0, 93.3, 98.1 and 90.4%, respectively. The AD of AAs was generally highest in the fermented dogfish feedstuff. A quality evaluation of the silages was conducted in a completely randomized design with four replications (two replications for AAs), to determine storage stability of the silages, on 10 different sampling days (days 1, 3, 6, 9, 15, 30, 90, 180, 270 and 360), (three sampling days for AAs) post-manufacture. The ASD was stable up to 180 d, after this storage time it underwent increases in pH and total volatile nitrogen (TVN) and decreases in N and AA content. The preservation of dogfish with a fermentation method (FSD) was judged to be unsuccessful with this feedstuff having a high initial pH (6.4) and large increases in TVN content early in storage. It was concluded that feedstuffs made from dogfish would provide a source of highly digestible nutrients for mink; however, more research is required before a fermented dogfish feedstuff can be incorporated into practical mink diets. , 3, 6, 9, 15, 30, 90, 180, 270 et 360 jours (3 dates seulement pour les AA) après la fabrication. L'ensilage acide demeurait stable jusqu'à 180 jours de conservation, après quoi son pH et les concentrations en N volatil total (NVT) augmentaient et les teneurs en N total et en AA diminuaient. La conservation du poisson par fermentation (RF) était jugée insatisfaisante, l'aliment ayant un pH initial élevé (6,4) et acquérant des teneurs en élevées en NVT dès le début de la conservation. Les aliments confectionnés à partir de chair de roussette constitueraient donc une bonne source de nutriments hautement digestibles pour le vison. Les recherches devront toutefois se poursuivent avant qu'on puisse recomman...

Effects of dietary protein levels on digestibility of nutrients and growth rate in young female mink (Mustela vison)

“…Mink are carnivorous exclusively (Whitman, 1981) and have been shown to bioaccumulate Hg up to 10 times the levels found in other predator (Kucera, 1983; Stevens et al., 1997). Supply of quality proteins for animal feeding such as carnivore mink does not catch up with the requirement of husbandry (White et al., 1998). Protein is essential for normal metabolic functions and to maintain the physical activity in the mink.…”