Evaluation of a Partially De-oiled Microalgae Product in Nursery Pig Diets

The publication we are sharing today is a collaboration between the Department of Animal Science, the Department of Food Science and nutrition and the West Central Outreach and Research Center at the University of Minnesota. It is published in open access in the journal Translational Animal Science.

Objectives

The aim of this study was to evaluate the potential use of microalgae extract (MAE) as a feed ingredient in nursery pig diets.

Methods

300 weaned pigs were selected, blocked by initial body weight and allotted to 60 pens, with five pigs per pen. Ratio of gilts and barrows was balanced evenly. Pens within blocks were assigned randomly to one of five dietary treatments.

Dietary treatments included:

  1. corn and soybean meal (CON),
  2. CON with 1% MAE,
  3. CON with 5% MAE,
  4. CON with 10% MAE
  5. CON with 20% MAE.

Diets were formulated to meet the nutrient requirements of nursery pigs and fed using a 3-phase program, where each phase consisted of a 2-wk period.

Average Daily Gain (ADG), Average Daily Feed Intake (ADFI) and Gain to Feed (G:F) were measured weekly.

After 42 days, 30 pigs were harvested and intestinal samples were collected to measure mucosal length and goblet cell quantifications.

Results

Final body weight of pigs among pens consuming MAE was greatest when consuming 1, 5, or 10% MAE compared with those fed the control diet, but feeding 20% MAE was not different from the control diet. The greater final body weight appeared to be the result of greater ADG from days 1 and 7, due to a higher ADFI.

There was no effect of feeding MAE on G:F during most weigh periods except during days 15 to 21 when G:F increased in pigs fed MAE.

Feeding diets with MAE did not result in changes in intestinal architecture measured by the height of the intestinal mucosal or presence of mucus-producing cells in the jejunum. In contrast, the ileum of pigs fed the 5% MAE diet tended to have reduced mucosal height compared with that of pigs fed 20% MAE diet. Goblet cell area of the ileum was not affected by dietary treatments.

Link to the full article

Abstract

Although microalgae can be used as a source of energy and macronutrients in pig diets, there is limited information on the use of partially de-oiled microalgae co-products in swine feeding programs. The objectives of this study were to evaluate the effects of a partially de-oiled microalgae extract (MAE) in nursery pig diets on growth performance and health status. A total of 300 pigs (initial BW = 6.3 ± 2.1 kg) were used in a 42-d experiment. Treatments included a standard corn-soybean meal control diet, and diets containing 1, 5, 10, or 20% MAE replacing primarily corn. The ME content of MAE was calculated from the chemical composition, and diets were formulated to meet or exceed nutrient requirements for nursery pigs. Pigs were stratified by weaning BW into 12 blocks in a randomized complete block design, with sex distributed evenly among blocks. Pens of pigs (5 pigs/pen) were assigned randomly within block to one of 5 dietary treatments. Pig BW and feed disappearance were recorded weekly. On d 42, thirty pigs were harvested and sections of the jejunum and ileum were collected for gut morphology analysis, and a liver sample was collected for metabolomic analysis using liquid chromatography-mass spectroscopy. Data were analyzed by ANOVA with diet as treatment effect, and contrasts were used to test linear or quadratic effects of dietary MAE inclusion level. Overall, pigs fed 1 and 5% MAE had the greatest (quadratic P < 0.05) ADG, resulting from greater (quadratic P < 0.05) ADFI. There was a tendency for a greater number of pigs requiring injectable treatments (P = 0.16) and a greater mortality (P = 0.14) in pigs fed the control diet than pigs in any of the diets with the MAE. Final BW increased (P < 0.05) for pigs fed 1 and 5% MAE diets. The improvements in ADG were not explained by differences in mucosa height or goblet cell count among dietary treatments. Pigs fed diets containing 1 or 5% MAE had relatively less concentration (P < 0.05) of ammonia in the liver and had changes in metabolites associated with the urea cycle. In conclusion, feeding MAE resulted in increased growth responses and may have beneficial health effects when fed to nursery pigs.