We have just submitted a scientific article comparing the protein value of different microalgae species to that of soybean meal in the nutrition of lactating dairy cows. In this paper, we present results from physiological experiment where we evaluated Spirulina platensis, Chlorella vulgaris or mixture of Chlorella vulgaris and Nannochloropsis gaditana as protein supplements for dairy cows in comparison to soybean meal. The experiment was conducted in University of Helsinki, Finland.

The key findings of this paper:

• Compared to soybean meal, microalgae did not affect total dry matter intake, but changed the quality of feed intake by decreasing the concentrate:forage ratio in the diet. This was caused by the poor palatability of microalgae, which has been observed also on our previous studies with microalgae.
• Statistical differences were not found in milk or energy corrected milk yield when soybean meal was substituted by microalgae. However, it is notable that microalgae diets resulted in numerically +2.2 kg/d higher energy corrected milk yield than soybean meal! Numerically highest milk yield was observed on Spirulina platensis diet.
• Spirulina platensis diet also increased milk fat production.
• Also environmental-wise, microalgae diets performed better than soybean meal as indicated by lower secretion of urinary nitrogen and urinary urea nitrogen, the most susceptible forms of nitrogen for environmental losses.
• Mixture of Nannochloropsis gaditana and Chlorella vulgaris resulted in fourfold increase in milk eicosapentaenoic acid (EPA) concentration compared to other diets without signs of milk fat depression.
• Unfortunately, the results of this experiment were confounded by concentrate related feed intake problems on microalgae diets on some but not all animals which lead to large standard errors in the data set. Therefore, statistical significance was not reached in some parameters (such as milk or energy corrected milk yield) despite of large numerical differences between treatments.
• In conclusion, microalgae are suitable protein feeds for dairy cows, and different microalgae species are at least as good protein feeds as soybean meal in the nutrition of lactating dairy cows especially if palatability of microalgae diets can be improved.

We are hoping for a quick review process after of which we are able to share more information about our recent findings! In the following papers we will prove that methionine-rich Spirulina platensis complements the amino acid composition of faba beans (Vicia faba) in the nutrition of dairy cows and study the effect of microalgae feeding on the phosphorus emissions of dairy cow production.

Article details:

• Authors: Marjukka Lamminen, Anni Halmemies-Beauchet-Filleau, Tuomo Kokkonen, Seija Jaakkola and Aila Vanhatalo
• Title: Different microalgae species as a substitutive protein feed for soya bean meal in grass silage based4 dairy cow diets
• Submitted to: Animal Feed Science and Technology