The study was carried out to evaluate three microalgae as potential nutrient sources in diets for monogastric animals. In a digestibility experiment with adult mink (Mustela vison), the microalgae Nannochloropsis oceanica, Phaeodactylum tricornutum and Isochrysis galbana were fed at 60, 120 and 240 g kg -1 as is, replacing fish meal. The N. oceanica and P. tricornutum had similar crude protein (CP) content (47.7 and 49.0% of DM, respectively), amino acid composition and lipid content (8.4 and 7.4%, respectively), whereas I. galbana contained 20.1% CP and 16.2% lipids. There was a significant linear reduction in CP digestibility with increasing dietary inclusion of all algae products. The apparent CP digestibility determined by linear regression for N. oceanica, P. tricornutum and I. galbana was 35.5, 79.9 and 18.8%, respectively. The individual amino acid digestibilities showed acceptable values for P. tricornutum, but low and highly variable values for N. oceanica and I. galbana. Although the algae contributed a minor proportion of dietary lipids, lipid digestibility declined with increasing inclusion of all algae and especially with the highest level of N. oceanica. It was concluded from the mink study that among the investigated algae, P. tricornutum was the preferable source of digestible nutrients.

Six experiments were conducted to evaluate the use of fat in diets containing a high level of milk products for weanling pigs. In Exp. 1, 192 pigs (6.6 kg and 23 d) were used to determine whether milk products (0 or 40%) in the diet influenced the utilization of fat (0 or 10%). No fat x milk product interactions were found. Adding milk products to the diet improved (P < .01) ADG, ADFI, and gain/feed (G/F). Adding fat to the diet did not influence performance. In Exp. 2, 3, and 4, 576 pigs (6.0 kg and 20 d) were used to determine the influence of fat level on performance. Adding soybean oil (0, 3, 6, or 9%) to the diet from d 0 to 14 after weaning had no influence on growth performance. Increasing soybean oil (0, 2, 4, or 6%) in the diet from d 14 to 35 had no influence on ADG; however, G/F improved linearly (P < .001). In Exp. 5, 196 pigs (7.5 kg and 26 d) were used to determine the influence of fat source (soybean oil, corn oil, or tallow) on performance. Pig performance was not different among fat sources. In Exp. 6, 240 pigs (5.4 kg and 21 d) were used to determine the influence of fat and(or) milk product inclusion in the nursery diet on subsequent grow-finish performance. Adding milk products, but not fat, to the nursery diet improved (P < .08) overall performance to market weight. These results indicate adding fat to the diet from d 0 to 14 after weaning had no influence on performance. Adding fat to the diet from d 14 to 35 improved G/F; however, it did not improve ADG or overall performance to market. Diet composition during the nursery period can affect subsequent performance.

Two growth experiments and one digestibility experiment were conducted to study the effect of trimethylamine oxide (TMAO) and betaine in swine diets. In Exp. 1, 36 limit-fed pigs averaging 19.1 kg in initial weight were used to study the effect of adding TMAO at 10 g/kg of feed or betaine at an equivalent level of methyl groups (10.5 g/kg feed) to a high-fat (11.3% ether extract) basal diet. Dietary addition of TMAO increased ADG by 61 g/d, reduced number of days to market by 8.3 d (P<.02), and tended (P<.09) to improve gain/feed (G/F) compared with the control diet. Betaine had no effect on growth performance of pigs. Adding TMAO or betaine to diets had no effect on percent carcass fat, percent carcass lean, or dressing percentage. Dietary supplementation of TMAO reduced (P<.05) plasma triacylglycerol level (TAG) compared with the control diet. There was no effect of dietary TMAO or betaine on sensory quality characteristics of pork. In Exp. 2, 48 ad libitum-fed pigs averaging 21.7 kg initial BW and 104.7 kg final BW were used to determine the effect of adding low and intermediate levels of TMAO (1, 2, or 5 g/kg) to diets. Adding 1 g of TMAO increased G/F (P<.01) compared with control pigs. When using orthogonal contrasts, adding 2 g of TMAO reduced (P<.05) P2 backfat thickness and tended to increase (P<.09) lean percentage compared with the control diet. Trimethylamine oxide gave a quadratic effect (P<.05) on plasma TAG levels. Adding 1 and 2 g of TMAO increased plasma TAG, but 5 g of TMAO decreased it compared with the control diet. In Exp. 3, 12 barrows of 42.3 kg average initial BW and 50.0 kg final BW were used to investigate the effect of supplementing diets with 1 g of TMAO and 1.27 g of betaine/kg of feed on apparent total tract nutrient digestibility. The addition of TMAO increased (P<0.03) apparent total tract digestibility of fat (HCl-EE). Betaine had no such effect. Adding TMAO to diets influenced growth performance and carcass quality in a dose-dependent manner.

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Kjos, N. P., Herstad, O., Øverland, M. and Skrede, A. 2000. Effects of dietary fish silage and fish fat on growth performance and meat quality of broiler chicks. Can. J. Anim. Sci. 80: 625-632. Two experiments were conducted to study the effect of concentrated fish silage and additional fish fat on growth performance (exp. 1) and meat quality (exp. 2) of broiler chicks. In exp.1, 600 day-old male and female chicks with an initial weight of 36.3 g ± 0.6 SD were allocated to five treatment groups. The treatments were a control diet, two test diets with 50 g kg -1 fish silage and different levels of fish fat (6 or 8 g kg -1 ), and two diets with 100 g kg -1 fish silage and different levels of fish fat (8 or 10 g kg -1 ). In exp. 2, 150 day-old female chicks with an initial weight of 36.3 g ± 0.7 SD were allocated to five treatment groups. The treatments were a control diet, and one of four test diets containing 50 g kg -1 fish silage and different levels of fish fat (2, 9, 17 or 25 g kg -1 ). In exp. 1, chicks fed diets with fish silage had a greater weight gain (P < 0.001), a greater feed intake (P < 0.05) and a lower feed-to-gain (MJ ME kg -1 ) (P < 0.001) than those fed the control diet. In exp. 2, no significant differences in weight gain or carcass weight were found among diets. The proportions of the fatty acids C18:3, C20:1, C20:5, C22:5 and C22:6 in abdominal fat, and C20:1, C22:1, C22:5 and C22:6 in breast meat, increased by the dietary inclusion of fish silage and fish fat. Increasing levels of dietary fish fat decreased blood plasma levels of vitamin E and ceruloplasmin. The diets containing the highest levels of fish fat (16.8 or 24.8 g kg -1 ) caused off-odour and off-taste of thigh meat stored at -16°C for both six months and one month.