This study was to determine the effect of the organic raising system (OR) on growth performance, meat quality, and physicochemical properties of slow-growing chickens. Three hundred and sixty (one-day-old) Korat chickens (KRC) were randomly assigned to control (CO) and OR groups. The groups comprised six replicates of thirty chickens each. The chickens were housed in indoor pens (5 birds/m²), wherein those in OR had free access to Ruzi pasture (1 bird/4 m²) from d 21 to d 84 of age. In the CO group, chickens were fed with a mixed feed derived from commercial feedstuffs, while those in the OR group were fed with mixed feed derived from organic feedstuffs. The results revealed a lower feed intake (p < 0.0001) and feed conversion ratio (p = 0.004) in the OR. The OR increased total collagen, protein, shear force, color of skin and meat, and decreased abdominal fat (p < 0.05). The OR improved fatty acid with increased DHA, n-3 PUFA, and decreased the ratio of n-6 to n-3 PUFA in KRC meat (p < 0.05). The synchrotron radiation-based Fourier transform infrared spectroscopy and correlation loading analyses confirmed these results. In conclusion, our results proved that OR could improve growth performance and meat quality and suggested the raising system be adopted commercially. In addition, the observed differences in biochemical molecules could also serve as markers for monitoring meat quality.

This study proposes a strategy to manipulate the fatty acid (FA) content in slow-growing Korat chicken (KRC) meat using tuna oil (TO). To determine the optimal level and feeding period of TO supplementation, we conducted a study investigating the effects of dietary TO levels and feeding periods on meat quality, omega-3 polyunsaturated fatty acid (n-3 PUFA) composition, and gene expression related to FA metabolism in KRC breast meat. At 3 wk of age, 700 mixed-sex KRC were assigned to seven augmented factorial treatments with a completely randomized design, each consisting of four replicate pens containing 25 chickens per pen. The control group received a corn-soybean-based diet with 4.5% rice bran oil (RBO), while varying amounts of TO (1.5%, 3.0%, or 4.5%) replaced a portion of the RBO content in the experimental diets. The chickens were fed these diets for 3 and 6 wk, respectively, before being slaughtered at 9 wk. Our results indicated no significant interactions between TO levels and feeding periods on the growth performance or meat quality of KRC (P > 0.05). However, the liver fatty acid-binding protein gene (L-FABP, also known as FABP1), responsible for FA transport and accumulation, showed significantly higher expression in the chickens supplemented with 4.5% TO (P < 0.05). The chickens supplemented with 4.5% TO for a longer period (3 to 9 wk of age) exhibited the lowest levels of n-6 PUFA and n-6 to n-3 ratio, along with the highest levels of eicosapentaenoic acid, docosahexaenoic acid, and n-3 PUFA in the breast meat (P < 0.05). However, even a short period of supplementation with 4.5% TO (6 to 9 wk of age) was adequate to enrich slow-growing chicken meat with high levels of n-3 PUFA, as recommended previously. Our findings indicated that even a short period of tuna oil supplementation could lead to desirable levels of omega-3 enrichment in slow-growing chicken meat. This finding has practical implications for the poultry industry, providing insights into optimal supplementation strategies for achieving desired FA profiles without adversely affecting growth performance or meat quality.

This research aimed to investigate the optimization of lipid-based nanoparticles to improve the utilization of n-3 PUFA source in chicken diets. Three groups of slow-growing Korat chickens were reared under the same conditions and fed a diet containing 6 % rice bran oil (RBO, control group), 3 % tuna oil (3 % TO) and 3 % tuna oil in targeted lipid-based nanoparticles (3 % TO-TNP). The growth performance, carcass composition, meat quality, fatty acid profile of breast and thigh meat, hematological and plasma biochemical parameters were evaluated. The dietary lipid source had no effect on the growth performance, carcass composition, or breast and thigh meat quality (P > 0.05). Compared to the control group, the 3 % TO and 3 % TO-TNP groups exhibited lower levels of C18:2n-6 (linoleic acid) and n-6 PUFA (P < 0.05). There was no significant difference between groups in the C18:3n-3 (ALA) level in breast and thigh meat, whereas the levels of C20:5n-3 (EPA) and C22:6n-3 (DHA) were higher in both TO groups. However, due to the high temperature required during the drying step of the nanoparticle synthesis process, n-3 PUFA enrichment was more efficient when TO was directly incorporated into the diet than when using targeted nanoparticles. Nevertheless, there was no difference between the 3 % TO and 3 % TO-TNP groups in the n-6/n-3 ratio (P > 0.05). The hemoglobin and hematocrit values were higher in 3 % TO-TNP than in the other groups (P < 0.05). In the plasma, HDL level was reduced in the TO groups compared to the control group (P < 0.05) suggesting a lower cholesterol hepatic synthesis and export. The TO groups had a higher activity of alanine amino transferase but a lower creatinine content than the control group (P < 0.05). The uric acid content was higher in 3 % TO-TNP group than in the 3 % TO group (P < 0.05) but no different compared with the control group. However, the values obtained for the hematological and biochemistry parameters measured in blood and plasma were within the normal range for chickens. To conclude, the supplementation of lipid-based nanoparticles allowed for change the fatty acid composition of chicken meat without any negative effect on production and health status of chickens.

This study investigated the effects of curcumin (CUR)- and capsaicin (CAP)- loaded nanoemulsion on blood biochemical changes, oxidative status, jejunal morphology, inflammatory parameters, and performance of slow-growing Korat chickens (KRC) raised under high stocking density (HSD). A total of 480 male KRC (21 d of age) were allocated into four groups: (1) HSD without supplementation, (2) normal stocking density (NSD) without supplementation, (3) HSD supplemented with CUR and CAP in powdered form (P-CUR+CAP), and (4) HSD supplemented with CUR- and CAP-loaded nanoemulsions (NE-CUR+CAP). Chickens receiving NE-CUR+CAP showed no adverse changes in liver or kidney function compared with other groups. The heterophil-to-lymphocyte ratio was reduced in NE-CUR+CAP group relative to HSD group and was comparable with NSD and P-CUR+CAP groups (P < 0.05). NE-CUR+CAP also lowered levels of TBA in the liver and jejunum while enhancing hepatic superoxide dismutase activity compared with HSD group (P < 0.05). Villus height, villus height-to-crypt depth ratio, anti-inflammatory response, and cecal Lactobacillus counts were improved, whereas crypt depth and cecal Escherichia coli were reduced in the NE-CUR+CAP group (P < 0.05). Although feed intake, BW, and body weight gain were not affected, the feed conversion ratio was significantly lower in NE-CUR+CAP compared with HSD group (P < 0.05). In conclusion, NE-CUR+CAP mitigated oxidative stress and inflammation, improved intestinal health, and enhanced feed efficiency in slow-growing chickens raised under HSD.

Alternative rearing systems have been increasingly adopted to improve poultry welfare and product quality. This study investigated the effects of organic (OR), free-range (FR), and conventional (CO) rearing systems on growth performance, behavior, brain characteristics, fatty acid profiles, and meat quality of slow-growing Korat chickens (KRC). A total of 375 mixed-sex day-old chicks were randomly allocated to 15 pens (5 replicates per treatment) and reared until 91 days of age. All birds were housed indoors at 5 birds/m², while FR and OR groups were provided access to Ruzi pasture at 1 and 4 m²/bird, respectively, from day 21. Behavioral activities were recorded by video observation during days 84 to 91. At slaughter, feather condition, brain structure, and meat quality were evaluated. Results indicated that OR chickens had significantly lower feed intake and final body weight compared with CO and FR birds (P < 0.05). Conversely, CO birds exhibited poorer feather condition, particularly in the tail region (P < 0.05). Principal Component Analysis (PCA) revealed distinct behavioral patterns among rearing systems, with CO birds displaying higher frequencies of aggressive behaviors (pecking, fighting), whereas FR and OR birds showed greater expression of nutritive and resting behaviors. Chickens reared under FR and OR systems exhibited lower brain porosity and greater brain volume compared with CO birds (P < 0.05). Regarding meat quality, FR and OR systems increased collagen content and shear force, while FR meat showed the lowest drip loss (P < 0.05). Moreover, the OR system significantly increased total n-3 polyunsaturated fatty acid (PUFA) content in breast meat (P < 0.05). Collectively, these results indicate that environmental complexity shapes brain integrity and behavioral resilience in KRC. This supports the adoption of welfare-oriented management practices, such as pasture access, to reduce aggression and improve meat quality. Such an approach may facilitate premium product differentiation, enabling producers to offset the economic constraints associated with slower growth rates through added welfare and nutritional value.