The effects of microalgae (Tetradesmus obliquus, Spirulina platensis and Chlorella vulgaris) on the nutritional profile of broiler meat

A. Freiberga¹, A. Ilgaza¹, S. Jonova¹, S. Eglite¹, D. Gorbacevska¹, A. Plivca¹, K. Neiberts², M. Zolovs³⁴ and P. Semjonovs²

¹Latvia University of Life Science and Technologies, Faculty of Veterinary Medicine, K. Helmana street 8, LV-3004 Jelgava, Latvia
²University of Latvia, Institute of Biology, Laboratory of Industrial Microbiology and Food Biotechnology, O. Vaciesa street 4, LV-1004 Riga, Latvia
³Statistics Unit, Riga Stradins University, Balozu street 14, Riga, Latvia
⁴Daugavpils University, Institute of Life Sciences and Technology, Department of Biosystematics, Vienibas street 13, LV-5401 Daugavpils, Latvia
*Correspondence: Correspondence: anete.freiberga@lbtu.lv

Abstract:

This study investigated the effect of dietary supplementation with three edible microalgae species (Tetradesmus obliquus, Spirulina platensis, and Chlorella vulgaris) on the nutritional profile of broiler chicken meat. Ross 308 broilers were fed a standard diet enriched with 0.5% of one of the microalgae species over a 43-day fattening period. Meat samples from the breast and thigh muscles were collected on days 35 and 43 to analyse its nutritional profile. Although no statistically significant differences were observed in growth performance, several biologically differences became apparent. C. vulgaris administration was associated with an initial increase in thigh meat fat content on day 35, followed by a notable reduction by day 43, and led to higher protein and polyunsaturated fatty acid levels. However, it resulted in the highest omega-6/omega-3 ratio among the groups. S. platensis contributed to a more favorable fatty acid profile, with the lowest omega-6/omega-3 ratio and increased protein levels, particularly in breast meat. T. obliquus supplementation produced leaner meat, improved vitamin B₁₂content, and maintained a more balanced omega-6 to omega-3 ratio by day 43, suggesting a cumulative benefit with prolonged feeding. These findings indicate that each microalga has species-specific effects on broiler meat quality, supporting their potential use as sustainable functional feed ingredients tailored to specific nutritional goals in poultry production.

Key words:

broiler, chickens, Chlorella vulgaris, edible microalgae, fatty acids, meat quality, Spirulina platensis, Tetradesmus obliquus

Microalgae for biomethane production

V. Dubrovskis* and I. Plume

Latvia University of Agriculture, Faculty of Engineering, Institute of Energetics, Cakstes blvd 5, LV 3001 Jelgava, Latvia; *Correspondence: vilisd@inbox.lv

Abstract:

Competition for arable land between food and energy producers has begun in Latvia. Biogas producers are seeking to use the hitherto unused land. There is a need to investigate the suitability of various biomasses for energy production. Maize is the dominating crop for biogas production in Latvia, but it is expensive to grow. The cultivation of more varied biomass with good economics and low environmental impact is thus desirable. Microalgae can be grown in pipes, basins and also in open ponds. This paper shows the results from the anaerobic digestion of microalgae Chlorella vulgaris, cultivated with fertilizer Varicon in open pond and harvested on 27 October and centrifuged (Study 1). The anaerobic digestion process was investigated for biogas production in sixteen 0.75 l digesters, operated in batch mode at temperature 38 ± 1.0 °C. The average methane yield per unit of dry organic matter added (DOM) from digestion of Chlorella vulgaris was 0.331 l gDOM^-1. The second investigation (Study 2) used fresh biomass of Chlorella vulgaris harvested on 10–15 June with low dry matter content, as it was obtained from 4 m deep open pond without centrifugation. Anaerobic digestion process was provided in 4 digesters with volume of 5 l each. Average methane yield from the digestion of Chlorella vulgaris was 0.290 l gDOM^-1, which is comparable to methane yield obtainable from maize silage or other energy crop silages. Microalgae Chlorella vulgaris can be successfully cultivated for biogas production from May to October or at least 170–180 days in a year under the agro-ecological conditions in Latvia.

Key words: