Potential of Full-Fat Silkworm-Based Diets for Laying Quails: Performance and Egg Physical Quality

Live yellow mealworm (Tenebrio molitor) larvae: a promising nutritional enrichment for laying quails

The study aimed to evaluate the effect of supplementing live Tenebrio molitor (TM) larvae to laying quails (Coturnix japonica) as nutritional enrichment. Live performances, apparent digestibility of nutrients (including that of sole live TM larvae), egg physicochemical quality, sensory traits, and storage stability were considered in this experiment. Sixty laying quails were divided into 2 dietary groups (6 replicated cages/group; 5 quails/cage): a Control group received a basal diet for laying quails and a TM10 group was fed with the Control diet supplemented with live TM larvae (10% of the expected daily feed intake). For the digestibility trial, 30 laying quails were divided into 3 dietary groups: the first 2 groups were fed with the Control and TM10 diets, while the third group received ad libitum live TM larvae (TM100) as a complete replacement for the Control diet. Overall, no mortality was recorded during the trials. Quails fed TM showed a remarkable capability of digesting dietary chitin (P < 0.0001). TM100 quails showed the lowest digestibility for dry matter, crude protein, and energy, but that of ether extract was the highest (P < 0.001). The presence of live TM larvae stimulated quails' feed intake (P < 0.0001), but did not affect performance traits. Similarly, overall physicochemical quality attributes and storage stability were comparable in Control and TM10 eggs. The sensory features of quail eggs differed in TM10 vs. Control groups: TM10 eggs had the lowest overall flavor (P < 0.01), sulfur (P < 0.05) and greasy-oily (P < 0.01) intensities. Therefore, a 10% TM dietary supplementation is effective in stimulating feeding activity of quails, but it did not provide any productive improvement compared to a standard diet. Further studies should assess the possible beneficial effect of live TM supplementation on quail's gut health. The digestibility trial with the sole live TM larvae allowed to assess the specific nutritional value of this emerging feedstuff which is of utmost importance for future feed formulations.

Differential diagnosis of Eimeria species in farmed Japanese quails (Coturnix japonica)

Similarly to poultry industry, coccidiosis may cause significant economic losses also in the commercial quail industry, an emerging sector undergoing uneven development around the world. Although scant and mostly dated, the available literature reports detailed morphological and morphometric features of both oocysts and sporocysts of the Eimeria species hitherto recognized in Japanese quails, i.e. E. tsunodai, E. uzura, E. bateri, and E. fluminensis. Mixed infections are very common in the field and require an accurate differential diagnosis of diverse species of coccidia, identifying the highly pathogenic ones, in particular E. tsunodai (localized in the caeca), and E. uzura (localized in both caeca and small intestine). This goal is hampered by time-consuming laboratory procedures involving highly qualified staff and facilities, and poorly compatible with routine management practices in farmed quails. A supplemental difficulty is represented by the lack of nucleotide sequences available in GenBank. To overcome these issues, copromicroscopic and molecular analyses (amplifying the 18S rRNA region, and the internal transcribed spacers regions ITS1-5.8rRNA-ITS2) were performed on oocysts populations separately isolated from pools of 12 caecal and 12 cloacal contents collected from 240 naturally infected laying Japanese quails. Data on morphological and morphometric features of 1,000 sporulated oocysts were statistically compared, demonstrating the presence of different Eimeria species colonizing the 2 intestinal tracts. This result was also confirmed by PCR and phylogenetic analysis of the 18S rRNA gene. Overall results allowed to hypothesize the presence of E. uzura in our Japanese quails. Although a certain identification at species level was not obtained, the present study demonstrates that reasonable turnaround times of monitoring procedures performed on Japanese quail farms, shedding light on the in vivo and post-mortem differential diagnosis of coccidiosis can be achieved, and provide obvious benefits in disease understanding and control.