Successful Use of Geochemical Tools to Trace the Geographic Origin of Long-Snouted Seahorse Hippocampus guttulatus Raised in Captivity.

The global market of dried seahorses mainly supplies Traditional Chinese Medicine and still relies on blurry trade chains that often cover less sustainable practices targeting these pricey and endangered fish. As such, reliable tools that allow the enforcement of traceability, namely to confirm the geographic origin of traded seahorses, are urgently needed. The present study evaluated the use of elemental fingerprints (EF) in the bony structures of long-snouted seahorses Hippocampus guttulatus raised in captivity in two different locations (southern Portugal and Northern Spain) to discriminate their geographic origin. The EF of different body parts of H. guttulatus were also evaluated as potential proxies for the EF of the whole body, in order to allow the analysis of damaged specimens and avoid the use of whole specimens for analysis. The contrasting EF of H. guttulatus raised in the two locations allowed their reliable discrimination. Although no single body part exactly mimicked the EF of the whole body, seahorse trunks, as well as damaged specimens, could still be correctly allocated to their geographic origin. This promising forensic approach to discriminate the geographic origin of seahorses raised in captivity should now be validated for wild conspecifics originating from different locations, as well as for other species within genus Hippocampus.

Impacts of pineapple peel powder on growth performance, innate immunity, disease resistance, and relative immune gene expression of Nile tilapia, Oreochromis niloticus.

An 8-week growth trial was conducted to examine the efficacy of pineapple peel powder (PAPP) on growth rate and immunity of Nile tilapia, O. niloticus. Three hundred Nile tilapia (20.91 ± 0.11 g) were fed five diets containing different levels of PAPP at 0, 10, 20, 30 and 40 g kg-1 PAPP, respectively. After four and eight weeks of the feeding trial, growth rates, and immune responses were tested. A challenge test using Streptococcus agalactiae and relative immune gene expression were performed after eight weeks of PAPP feeding. It was found that skin mucus and serum lysozyme, skin mucus and serum peroxidase, alternative complement, phagocytosis, and respiratory burst activities were significantly increased with the addition of PAPP. The maximum (P ≤ 0.05) innate immune values were noted in fish fed 10 g kg-1 PAPP. Similarly, the up-regulation of IL1, IL8, and LBP gene expressions were also detected in fish fed PAPP diets, with the maximum value was found in 10 g kg-1 PAPP fed fish. The relative percentage of survival (RPS) of Oreochromis niloticus after the challenge test were (56.00%, 72.00%, 60.00%, and 44.00%) for the 5, 10, 20 and 40 g kg-1 PAPP diets, respectively. Fish fed the 10 g kg-1 PAPP supplemented diet achieved the highest (P < 0.05) survival rate against S. agalactiae. Growth and feed efficiency were outstandingly (P < 0.05) enhanced in the PAPP groups. In conclusion, PAPP can be potentially used as a feed additive in Nile tilapia culture under Biofloc system.