Acute and subchronic safety assessment of Porphyridium purpureum biomass in the rat model

Porphyridium purpureum biomass was assessed
for its acute and subchronic safety in albino Wistar rats and
for its use as animal feed/human food application.
P. purpureum contained 29.9 % protein, 7.99 % lipid, and
2.98 % phycoerythrin on dry basis. Polyunsaturated fatty
acids constituted >50 % of the total fatty acids (53.9 % w/
w), with eicosapentaenoic acid as the predominant ω3
(21.9 %) and arachidonic acid as the predominant ω6 fatty
acid (15.7 %) with an overall ω6/ω3 ratio of 0.42. The essential
amino acids (EAAs) constituted 37.97%(w/w) of proteins
with leucine as the predominant amino acid (10.99 %). The
EAA index was similar to casein and soybean proteins.Water
absorption capacity (WAC; 3.86±0.01 g water g−1 biomass)
and oil absorption capacity (OAC; 3.57±0.04 g oil g−1 biomass)
were six times higher compared to the basal diet (WAC
0.66 ± 0.007 g wate r g− 1 feed and OAC 0.57 ±
0.02 g oil g−1feed). The acute toxicity study showed that the
biomass was safe at acute doses and LD50 exceeded 5.0 g kg−1
body weight, the highest dose used in the study. In a subchronic
study, rats were fed a diet containing 0, 2.5, 5.0, 7.5, and
10.0 % levels (w/w) for a period of 13 weeks. The biomass
fortification did not induce any untoward changes in physiology
such as body weight gain, relative organ weights, histopathology,
and hematological and serum biochemical indices.
However, supplementation of P. purpureum biomass resulted
in decreased serum cholesterol and triglyceride levels compared
to control groups indicating its high nutritional value.