Spirulina platensis is a supplement that has a good impact on the growth performance of lambs, but information about the amount of this substance in feed efficiency and environmental impact is still required to be determined. The study aimed to examine the effect of the supplementation level of Spirulina platensis in the basal diet on the productivity and environmental costs of Thin-tailed lambs fattening. Twenty-four male lambs (aged 4 months; weighing 14.99 kg) were allocated to a completely randomized design with 4 treatments and six replications in each treatment. The treatments were 1) 100% basal diet without Spirulina supplementation (T0); 2) 99.5% basal diet + 0.5% Spirulina platensis supplementation (T1); 3) 99.0% basal diet + 1.0% Spirulina platensis supplementation (T2); and 4) 98.5% basal diet + 1.5% Spirulina platensis supplementation (T3). The parameters observed were dry matter intake (DMI), nutrient utilization, rumen fluid and blood profile, productivity, feed cost and nitrogen excretion and methane emission. The results showed that DMI of T3 was the highest among the treatments (985.66 g/d; p 0.05) and higher than that of others (p 0.05) in average daily gain (ADG) and higher than that of the others. Feed conversion ratio (FCR) of T2 (4.74) was not significantly different from T3 (p > 0.05) but higher (p 0.05). Feed cost per gain (FC/G) of T2 (Rp 31,996/kgADG) was the lowest (p 0.05; averaged 0.035 g/kgADG) and lower (p < 0.05) than that of T0 and T1. Methane emission per kg ADG of T2 (11.52 L/ADG) was the lowest (p < 0.05) among the other treatments. In conclusion, the supplementation of Spirulina platensis up to 1% (T2) increased productivity, reduced feed cost and environmental cost of Thin-tailed lambs production.
Luthfi et al. (Wed,) studied this question.