Effect of the dietary inclusion of Spirulina platensis on the nutrient digestibility in the Guinea pig

This study aimed to study the nutrient digestibility of diets with or without inclusion of Spirulina platensis (a blue-green microalgae containing 65.8% crude protein, with potential antiobesity, hypocholesterolemic and antioxidant actions) in the Guinea pig (Cavia porcellus) by comparing a control diet (diet C) without Spirulina and an experimental diet (diet S) with 3% of Spirulina. The two diets were isoproteic (16.7 vs 16.6%) and isoenergy (16.8 vs 16.9 MJ/kg, for C and S diet, respectively) and were supplemented with 150 mg vitamin C/kg diet. Twenty adult guinea pigs of both sexes were divided into 2 homogeneous groups, individually housed in digestibility cages, and fed the 2 experimental diets during an adaptation period of 7 days and then the subsequent digestibility trial lasting 5 days. During the digestibility trial, feed consumption was measured and the faeces were collected individually for chemical analyses. ANOVA tested the effect of the diets, of the sex, and their interaction. Sex did not influence nutrient digestibility. The nutrient and energy digestibility of the 2 experimental diets appeared similar, contrary to the reduction in digestibility of nearly all nutrients observed in rabbits when fed Spirulina supplement. Spirulina inclusion increased fibre fraction digestibility, particularly haemicelluloses digestibility (49.6 vs 42.6%; P<0.05). Potassium digestibility was significantly higher in S diet compared to C diet (88.7 vs 81.0%; P<0.001), attributable to the high potassium content of Spirulina. Feed intake during the digestibility trial was slightly higher in the S group (0.23 vs 0.20 g DM/kg LW). The dietary inclusion of Spirulina did not affect nutrient digestibility substantially, and its supplementation in Guinea pig diets seems profitable for the coverage of protein requirements and animal health in general.