Spirulina and/or Canthaxanthin -Enriched Artemia Enhances Pigmentation, Performance, Immunity, Histology, and Somatolactin and Growth Hormone Gene Expression of Goldfish, Carassius auratus

Abstract

Abstract The ornamental fish industry faces a major challenge in enhancing the brilliant coloration desired by consumers. Therefore, the main objective of this study was to assess the influence of spirulina and/or canthaxanthin enriched artemia on the efficacy of goldfish pigmentation. Growth, blood analysis, immunity, histology, and the expression of the genes for somatolactin (SL) and growth hormone (GH) of goldfish were also evaluated. Goldfish (N = 225, 1.10 ± 0.02g) were tested with five experimental treatments as follows: (T1) fish fed a basal diet; (T2) fish fed a basal diet and un-enriched artemia (UEA); (T3) fish fed a basal diet and spirulina enriched artemia (SEA); (T4) fish fed a basal diet and canthaxanthin enriched artemia (CEA); and (T5) fish fed a basal diet and spirulina and canthaxanthin enriched artemia (SCA). The experiment lasted for 90 days. The results showed that T5 had the highest carotene concentration (3.446 mg/g), lowest chromatic deformity, and better growth performance and feed utilization (P ≤ 0.05). The best results in hematology, serum biochemical, and immunological tests were observed in goldfish treated with T5. In addition, histological examination of the intestine in T5 revealed a significant increase in villi length and goblet cells (#/mm2) in the anterior and middle intestine. Dietary effects on SL and GH gene expression in the liver and brain differed significantly among treatments. However, a significant increase in values was observed in all treatments except T1 and T2. The somatolectin alpha (SL-a) gene is expressed in the brain rather than the liver specially in T5.