Influence of Spirulina platensis on growth performance of weanling pigs.

Three experiments were conducted to evaluate the in uence of an algae derived feed additive, Spirulina platensis (SP), on weanling pig performance. In all experiments, pigs were blocked by weight and allotted to one of four (experiments 1 and 3) or six (Experiment 2) dietary treatments. Standard diets and feeding regimens were implemented in all three experiments and SP replaced soybean meal on an equal lysine basis. Zinc oxide (3000 mg Zn kgy1) and medication were included in the diets for only experiments 1 and 3. In Experiment 1, a control diet or diets containing 2, 5, or 20 g SP kgy1 were fed in a pellet form from days 0 to 14 after weaning followed by meal form from days 14 to 28 after weaning. From days 0 to 14, no differences in pig performance were observed. From days 14 to 28, a cubic (p < 0.05) response was observed for ADG and ADFI with pigs fed 20 g SP kgy1 having greater ADG than pigs fed the control diet. In Experiment 2, dietary treatments (meal form) consisted of a control diet (no SP, fed for 6 weeks), 1 g SP kgy1 (fed for 6 weeks) or 2 g SP kgy1 (fed for 1, 2, 4, or 6 weeks). Pigs were switched to the control diet at the end of each SP feeding regimen. From days 0 to 14 after weaning, no differences in ADG or ADFI were observed. Pigs fed diets containing 1 or 2 g SP kgy1 for the entire 28 days had better feed ef®ciency (p < 0.02) than the treatments in which SP had been removed from the diet on day 7 or 14 after weaning. However, from days 0 to 42 after weaning, no differences in ADG or ADFI were observed. In Experiment 3, dietary treatments were arranged in a 2 2 factorial with the main effects of feed processing (meal versus pellet) with or without 2 g SP kgy1. From days 0 to 14 after weaning, adding SP to pelleted diets numerically tended to decrease ADG (SP feed Animal Feed Science and Technology 83 (2000) 237±247 $ Contribution No. 99-360-J of the Kansas Agric. Exp. Sta., Manhattan 66506. * Corresponding author. Tel.: ‡1-785-532-4202; fax: ‡1-603-676-5543. E-mail address: dritz@vet.ksu.edu (S.S. Dritz). 1 Food Animal and Health Management Center, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5606. 0377-8401/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 7 8 4 0 1 ( 9 9 ) 0 0 1 3 0 3 processing, p < 0.10), whereas adding SP to meal diets tended to improve ADG. From days 14 to 28 or days 0 to 28 after weaning, no differences in ADG, ADFI, or F/G were observed. In conclusion, the response to SP was inconsistent and occurred only with meal diets. # 2000 Elsevier Science B.V. All rights reserved.