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.

One digestibility experiment (Exp. 1) and two growth experiments (Exp. 2 and 3) were conducted to evaluate the use of lecithin as an emulsifier of soy oil and(or) an energy source in a two-phase starter diet program. Phase 1 consisted of d 0 to 14 postweaning, and Phase 2 consisted of d 14 to 35 postweaning. Diets were based on corn, soybean meal, and 20% dried whey and contained a constant ME:lysine level. In Exp. 1 and 2, two levels of lecithin (0 and 2%) at two levels of soy oil (0 and 6%) were investigated. In both experiments, there was no interaction between lecithin and soy oil for any traits measured. In Exp. 1, the apparent digestibility of fat increased significantly with increased fat level in the diets. Addition of lecithin to diets improved (P < .05) nitrogen retention, and the addition of soy oil significantly improved apparent digestibility of DM, GE, fat, and CP. In Exp. 2, there was no significant effect of lecithin or soy oil on ADG. In Phase 2 and overall, the inclusion of lecithin and soy oil to diets significantly increased gain/feed but did not significantly improve gain/ME intake. In Exp. 3, pigs were fed diets containing 0, 1, 2, or 3% lecithin. The addition of lecithin to diets did not affect ADG, ADFI, gain/feed, or gain/ME intake during Phases 1, 2, or overall. These results fail to demonstrate that the addition of lecithin to diets for young pigs improves utilization of soy oil or growth performance.

Kjos, N. P., Skrede, A. and Øverland, M. 1999. Effects of dietary fish silage and fish fat on growth performance and sensory quality of growing-finishing pigs. Can. J. Anim. Sci. 79: 139-147. Thirty-six growing-finishing pigs, with an average initial weight of 24.8 kg ± 2.6 SD, were allocated to six groups to determine the effect of fish silage and fish fat in the diet on performance, carcass characteristics and sensory quality. The treatments were either a control diet, or one of three diets containing 50 g kg -1 fish silage and different levels of fish fat (2.5, 5.5 or 9.5 g kg -1 ). The diets were either fed until the time of slaughter (treatments CO, FSA1, FSB1 and FSC1), or until 60 kg liveweight followed by the control diet (the diets with 5.5 [treatment FSB2] and 9.5 g kg -1 fish fat [treatment FSC2]). Pigs were slaughtered at 98.7 kg ± 4.5 SD. No significant differences in growth performance or carcass quality were found among diets. The contents of the fatty acids C20:1 and C22:6 in the subcutaneous fat was increased by the dietary inclusion of fish silage. The total level of omega-3 fatty acids were highest for the 9.5 and the 5.5 g kg -1 fish fat diets when they were fed until slaughter. High blood plasma levels of vitamin E in pigs fed diets containing fish silage and 5.5 g kg -1 fish fat may explain these differences, and thus indicate the importance of vitamin E status when feeding diets containing fish silage and fish fat. The diets containing 2.5 and 9.5 g kg -1 fish fat until slaughter caused off-flavour of bacon after both 1 and 6 mo of frozen storage, and of loin muscle after 6 mo frozen storage. Curiously, the diet with fish silage and 5.5 g kg -1 fish fat could be used in diets for growing-finishing pigs without adverse effects.

Four barrows of approximately 40 kg initial body weight, fitted with post-valvular T-cecum cannulas, were used to study the effect of lecithin as an external emulsifier on apparent ileal and overall digestibility of crude fat, fatty acids, and other dietary nutrients (DM, N, GE, crude fiber [CF], P, Ca, and Mg), as well as the utilization of N, GE, Ca, P, and Mg. Two levels of lecithin (0 and .24%) and two levels of rendered fat (0 and 6%) in cereal-soybean meal-based diets were investigated according to a 4 x 4 Latin square design. No significant interactions were found between lecithin and rendered fat for apparent digestibility of crude fat as estimated at the end of the small intestine and the total digestive tract. Lecithin decreased the apparent ileal digestibility of C16:0 fatty acid (P < .1) and the apparent overall digestibility of C14:0 fatty acid (P < .05) and C18:2 fatty acid (P < .1). The apparent ileal and overall digestibility of crude fat (P < .001) and total fatty acids (P < .05) increased with the inclusion of rendered fat in diets. Furthermore, rendered fat increased the apparent ileal and overall digestibility of C14:0 (P < .01), C16:1 (ileal, P < .001; overall, P < .1), and C18:1 (P < .05) fatty acids and the apparent overall digestibility of C18:0 (P < .001) fatty acid. Lecithin had no impact on the apparent digestibility and retention (percentage of intake) of GE, N, total P, Ca, and Mg.(ABSTRACT TRUNCATED AT 250 WORDS)