Pulsed electric field (PEF) processing of microalga Chlorella vulgaris and its digestibility in broiler feed

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Sofie Van Nerom, Kobe Buyse, Filip Van Immerseel, Johan Robbens, and Evelyne Delezie

Van Nerom, S. et al (2024) Pulsed electric field (PEF) processing of microalga Chlorella vulgaris and its digestibility in broiler feed. Poultry Science 103:103721 https://doi.org/10.1016/j.psj.2024.103721.


Microalgae have potentially beneficial  effects  on  animal  health  and nutritional value when added  to  feed. Crucial  hereby  is that intracellular  bio-active molecules are released in  the intestinal tract. Digestibility of Chlorella vulgaris and its impact on total digestibility of broiler feed is a first step in assessing its characteristics as feed supplement. Different methods could be used to increase the digestibility of the algae. Among other, pulsed electric field (PEF) and freezing to disrupt autotrophic(A) and heterotrophic(H) Chlorella vulgaris cells was assessed to increase their availability followed  by in-vivo trials. In these trials effect of algae type (A and H) and effect  of  PEF-processing  was  evaluated on the  apparent nutrient digestibility. PEF showed to have a disruption efficiency of 83.90% and 79.20% for heterotrophic and autotrophic C. vulgaris respectively. Freezing C. vulgaris only showed efficiencies ranging from 3.86% to 11.58%.Microscopic counting of intact C. vulgaris cells showed an increase in digested intact C. vulgaris cells of PEF-processed C. vulgaris compared to non-processed cells ranging from 12.16% to 15.20%. Autotrophic C. vulgaris had a higher digestibility compared to heterotrophic C. vulgaris, with an increase of 7.29%, 9.44% and 17.29% in digestibility of C. vulgaris in the 1,  2  and  5%  feed  respectively. Feeds  with  PEF-processed C.  vulgaris showed  no  significant increase in digestibility compared to non-processed C. vulgaris supplemented feeds. The 5% C. vulgaris feeds showed lower fat digestibility than the 1and 2% and control feeds. Protein digestibility  was lower  for  all C.  vulgaris feeds  compared  to  the  control  feed. There  was  a significant linear decreasing effect (P < 0.001) for all digestibility parameters. Except for crude ash digestibility, which first lowered for the 1 and 2% feeds, but then increased at 5% inclusion. Considering this study, including low dosages of 1 and 2% of C. vulgaris in broiler feed does not compromise its digestibility.

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Poultry Science