USE OF SILVER HAKE AND HERRING AND THE CORRESPONDING SILAGES IN MINK DIETS DURING THE GROWING-FURRING PERIOD

Atlantic herring (Clupea harengus) and silver hake (Merluccius bilinea ris) are readily available in Atlantic Canada either as processing was te or by-catch of the fishery. There is a vital need to reduce the cos t of production in the mink industry, of which feed cost is a major pr oportion. A research effort was therefore targeted on the use of local ly available opportunity feeds including silver hake and herring. A gr owth trial was conducted with 192 mink of standard genotype from mid-A ugust until pelting in December 1991. There were eight dietary groups as follows: two dry and six wet diets, with 12 male and 12 female mink in each. The dry diet groups were: control, commercial dry diet (COMD RY) and experimental dry diet (NSACDRY). The wet diets were: 10% silve r hake (HAKE10), 5% silver hake silage (HASIL5), 10% silver hake silag e (HASIL10), 10% herring in the diet (HER10), 5% herring silage (HERSI L5), and 10% herring silage (HERSIL10). The basal wet diet mixture con sisted of; haddock offal (30-35%), chicken offal (10%), beef offal (15 %), corn gluten meal (5%), extruded wheat (12%), rendered lard (1-2%), vitamin-mineral premix (0.4%) and water. The fish silages were preser ved with formic acid (2% volume to weight). Body weight gain of the an imals was normal throughout the study. At pelting, the females in the HAKE10 (1043.0 +/- 43.2 g, 59.1 +/- 1.0 cm), HASIL10 (1157.4 +/- 45.1 g, 61.3 +/- 1.1 cm), HER10 (1078.9 +/- 45.1 g, 59.6 +/- 1.1 cm), HERSI L5 (1090.5 +/- 43.2 g, 59.8 +/- 1.0 cm), and HERSIL10 (1057.8 +/- 43.2 g, 58.6 +/- 1.0) were significantly heavier and their processed pelts significantly longer, respectively, than in the females in the COMDRY group (910.7 +/- 47.3 g, 55.4 +/- 1.1 cm) (P < 0.05). In addition, th e final weight of the females in the NSACDRY group (1051.6 +/- 43.2 g) differed from the control (P < 0.05). There were no significant diffe rences in the traits measured for the males among different treatments . No deleterious effects on the health of the animals fed the test die ts were observed when evaluated by haematology, serum clinical chemist ry and histopathology. Both herring and silver hake and the correspond ing fish silages at 10% of the diet show good potential as alternative feedstuffs in growing-furring diets for mink.