[Incorporation of a spiruline (Spirulina maxima) in swine food].

Two experiments on early weaned piglets and one experiment on sows during the first two reproductive cycles were made to determine the nutritive value of Spirulina maxima algae in the pig, taken as a "nutritional model" for man. The algae were introduced into the diets of the piglets, between 12 and 42 days of age, in a proportion representing 12 p. 100 of the total proteins. This level corresponded to 12 p. 100 algae in the first age feed (up to 21 days) in replacement of skim milk, and 8 p. 100 of the second age feed in replacement of soyabean meal. For the overall experimental period, from 12 to 42 days, the apparent digestibilities of the diets, measured by the chronium oxide marking, decreased by 6.9 and 6.1 points, respectively, for energy and total crude proteins as compared to the control diet. Replacement of the same raw materials by a soluble fish protein concentrate only led to a reduction of 2.9 and 3.5 points for energy and proteins. However, during the first week following weaning, the fish concentrate and spirulina gave identical results which were lower than those of the control (fig. 1). In spite of this lowering in the apparent digestibility the growths of the piglets were satisfactory and equivalent for all groups. Thus, the mĕtabolic utilisation of the fraction of feed absorbed was better for the spirulina group than for the control group, notably during the period between 12 to 21 days, although the supply of lysine in the spirulina group was 12 p. 100 lower (tab. VII). Consequently, this partially compensates for the low apparent digestibility of the algae in the young animal. For the female, the spirulina algaes were continously administered in a proportion of 5 p. 100 of the diet from a live weight of 75 kg. This did not change either the age or the weight at onset of puberty (tab IX). During the first reproductive cycle, the net weight gain of the sows receiving spirulina was lower than that of the control sows, but the number of piglets and the weight of the litter were higher (tab X). During the second cycle, performances were almost identical for the two groups, but piglets from the spirulina sows were slightly heavier than those from the control sows, in corelation with smaller litters (tab XI). During lactation, the lipid content of the milk was not substancially modified by addition of spirulina to the diet (tab. XIII). At the end of the two reproductive cycle the characteristics of the two groups of sows were identical, with a slightly higher culling rate for the spirulina group, but without direct relationship with the use of algae. Furthermore, the productivity of the sows was the same: 16.34 piglets weaned per sow and per year for the controls and 15.99 for the spirulina sows. Thus, if considering spirulina as a protein supplement to traditional proteins, its use in pig feeding does not seem to give rise to particular problem. However, it is advisable to restrict their supply to a level not exceeding 25 p...