Dietary supplementation with natural antioxidants: assessment of growth performance and meat quality in broiler chickens.

Exposure to air and light lowers the meat quality of chickens, which is mainly determined by the color alteration and accumulation of detrimental products from lipid oxidation. This study tests the effects of 2 supplements rich in polyphenols, Oxilem (OX) and OxiGem (OG), on broiler Ross 308 performance and meat quality in comparison to a control group (C). A total of 105 one-day-old Ross 308 male chicks were allocated to 21 pens and randomly assigned to 1 of the 3 treatments. The trial lasted 42 d. Individual live weight and feed intake per pen were recorded. Proximate analysis, color, cholesterol content and cholesterol oxidation products (COPs), fatty acids (FAs), volatile aldehydes profile, and secondary oxidation products of meat FAs were determined, with analyses for detecting oxidative alterations conducted on breast burgers preserved for 7 d at 4°C. Birds fed OG grew 7 g/d more than those receiving OX, reaching a higher final weight. After slaughtering, meat from the OX group had a higher yellow index compared to C. After 7 d of air and light exposure, the influence on the color parameters of the OG and OX burgers was significantly less pronounced than that of C. Secondary oxidation products of the FAs of the burgers were not significantly affected by the diet regimens. In addition, OX and OG burgers exhibited lower amounts of volatile aldehydes, triol and COPs. These results confirm the effectiveness of OX and OG supplementation against lipid oxidation at the inclusion level used in this trial.

The Application of Synthetic Flavors in Zebrafish (Danio rerio) Rearing with Emphasis on Attractive Ones: Effects on Fish Development, Welfare, and Appetite.

The aim of the present study was to test synthetic flavors as potential feed attractants in zebrafish (Danio rerio) during early development. Six experimental groups were set up in triplicate: (i) a CTRL group fed a zebrafish commercial diet; (ii) a PG group fed a control diet added with Propylene Glycol (PG); (iii) A1+ and A2+ groups fed a control diet added with 1% of the two attractive flavors (A1+ cheese odor made by mixing Propylene Glycol (PG) with the aromatic chemicals trimethyamine, 2-acetylpyrazine, 2-acetylpyridine, and dimethyl sulfide; and A2+ caramel odor, made of PG mixed with the aromatic chemicals vanillin, maltol, cyclotene, acetoin, butyric acid, and capric acid with traces of both gamma-octalactone and gamma-esalactone) or the repulsive flavor (A- coconut odor, made by mixing PG with the aromatic chemicals gamma-eptalactone, gamma-nonalactone, delta-esalactone, and vanillin with trace of both delta-octalactone and maltol), respectively; (iv) an ROT group fed the two attractive diets, each administered singularly in a weekly rotation scheme. All the tested synthetic flavors did not affect the overall health of larval and juvenile fish and promoted growth. Due to the longer exposure time, results obtained from the juvenile stage provided a clearer picture of the fish responses: zebrafish fed both attractive diets showed higher appetite stimulus, feed ingestion, and growth, while the brain dopaminergic activity suggested the A2+ diet as the most valuable solution for its long-lasting effect over the whole experiment (60-day feeding trial, from larvae to adults). The present study provided important results about the possible use of attractive synthetic flavors for aquafeed production, opening new sustainable and more economically valuable opportunities for the aquaculture sector.

Effect of different stunning methods on rigor mortis, shape, energetic status and physical characteristics of Salmo carpio fillets.

BACKGROUND: Consumer interest in safeguarding animal welfare and increased demand for fresh aquatic products support the need to understand the effects of stunning methods used in aquaculture on the biochemical process affecting fish fillet quality. The present paper aimed at comparing electrical stunning (ES) and cold shock (ICE) in Salmo carpio, an Italian endemic under-investigated species. Rigor mortis evolution, fillet adenosine 5'-triphosphate (ATP), shape, colour, pH and water holding capacity were assessed by integrating chemical and image analyses. RESULTS: Seventy-two fish (24 fish per treatment) were stunned by ES, ICE or anaesthesia (AN, used as control), then percussively slaughtered. ES and ICE hastened rigor mortis onset and resolution (21 and 28 h post mortem) compared to AN. This was confirmed by the faster ATP degradation in ES and ICE. Fillet shape features varied during rigor mortis, according to the stunning method, with the perimeter showing irreversible variation in ES and ICE groups. Initial circularity was recovered only in AN, while ICE and ES fillets showed significantly different values, between 0 and 192 h. CONCLUSION: ES is a promising stunning technique for S. carpio, but parameters should be optimized, because of the adverse effect on muscle activity which caused a fast pH drop, and the presence of blood spots in the fillets. Further studies are needed to understand whether fillet shape changes can interfere with filleting or fillet processing and consumer appreciation. © 2022 Society of Chemical Industry.

Towards the Identification of a Suitable Commercial Diet for Carpione (Salmo carpio, Linnaeus 1758): A Multidisciplinary Study on Fish Performances, Animal Welfare and Quality Traits.

Carpione (Salmo carpio, Linnaeus 1758) is an endangered precious endemism of Lake Garda (Northern Italy), the largest Italian lake. To date, several bottlenecks about its culture remain unsolved, including the identification of a proper growth-out diet. The aim of the present study was to test four different grossly isolipidic, isoproteic, and isoenergetic diets in which the main ingredients had a different origin. Specifically, a diet currently used by local farmers for carpione culture, largely based on marine ingredients, was used as control (CTRL), while the other three diets were formulated by partially replacing marine ingredients with plant ones (VEG) or with different percentages of processed animal proteins (PAP1 and PAP2). The feeding trial was run in triplicate, over a three-month period. No significant differences in growth performance among the experimental groups were observed. However, remarkable histological alterations and inflammatory markers upregulation were observed in VEG group, while PAP inclusion played a role in attenuating inflammation and improving nutrient uptake. Fillet analyses highlighted significant differences in marketable traits and flesh fatty acid composition among the experimental groups, including the reduction of polyunsaturated fatty acids related to PAPs inclusion. In conclusion, PAPs used in the present study promoted S. carpio gut health and absorption capacity, while further studies are required to maintain proper quality traits of the final product.

Low dietary inclusion levels of Tenebrio molitor larva meal slightly modify growth performance, carcass and meat traits of Japanese quail (Coturnix japonica).

BACKGROUND: Insect-derived proteins are a promising, valuable and permitted ingredient for poultry feed. However, more emphasis should be given to their effects on avian species different from chicken, such as quail (Coturnix coturnix), whose rearing represents an important activity. The present paper provides novel information about the impact of graded dietary levels of Tenebrio molitor (TM) larvae meal on quail growth and meat quality. RESULTS: Four diets were formulated with graded inclusion levels of TM, namely 1.65, 3.3 and 6.6 g on 100 g feed (T1.65, T3.3, T6.6, respectively) to partially replace the conventional proteins of a control diet (C). A total of 192 birds were allotted to one of the groups and fed for 35 days. The inclusion of TM meal linearly increased feed conversion ratio, and decreased carcass and breast weight. Texture and water holding capacity of meat were linearly reduced with increasing TM in diet, while fatty acid composition was not affected. However, the meat from quails fed diets including TM was subject to greater thermal damage than the C group; hence further studies are encouraged. CONCLUSION: TM meal inclusion at higher levels than 1.65% slightly impaired the growth performance of Japanese quails. Negligible effects on physical properties such as colour, texture, cooking loss and also on the fatty acid profile of the raw and cooked meat was found after including TM in quails' diet up to 3.3%. © 2022 Society of Chemical Industry.

Effects of Dietary Supplementation with Honeybee Pollen and Its Supercritical Fluid Extract on Immune Response and Fillet's Quality of Farmed Gilthead Seabream (Sparus aurata).

The awareness of the correlation between administered diet, fish health and products' quality has led to the increase in the research for innovative and functional feed ingredients. Herein, a plant-derived product rich in bioactive compounds, such as honeybee pollen (HBP), was included as raw (HBP) and as Supercritical Fluid Extracted (SFE) pollen (HBP_SFE) in the diet for gilthead seabream (Sparus aurata). The experiment was carried out on 90 fish with an average body weight of 294.7 ± 12.8 g, divided into five groups, according to the administration of five diets for 30 days: control diet (CTR); two diets containing HBP at 5% (P5) and at 10% (P10) level of inclusion; two diets containing HBP_SFE, at 0.5% (E0.5) and at 1% (E1) level of inclusion. Their effects were evaluated on 60 specimens (336.2 ± 11.4 g average final body weight) considering the fish growth, the expression of some hepatic genes involved in the inflammatory response (il-1ß, il-6 and il-8) through quantitative real-time PCR, and physico-chemical characterization (namely color, texture, water holding capacity, fatty acid profile and lipid peroxidation) of the fish fillets monitored at the beginning (day 0) and after 110 days of storage at −20 °C. The results obtained showed that the treatment with diet E1 determined the up-regulation of il-1ß, il-6, and il-8 (p < 0.05); however, this supplementation did not significantly contribute to limiting the oxidative stress. Nevertheless, no detrimental effect on color and the other physical characteristics was observed. These results suggest that a low level of HBP_SFE could be potentially utilized in aquaculture as an immunostimulant more than an antioxidant, but further investigation is necessary.

Different Combinations of Butchery and Vegetable Wastes on Growth Performance, Chemical-Nutritional Characteristics and Oxidative Status of Black Soldier Fly Growing Larvae.

Hermetia illucens larvae (five days old) were farmed on broiler feed (control diet), a vegetable diet (V100), a 50% of vegetable diet + 50% of butchery wastes (V50 + B50), and a 75% of vegetable diet + 25% of butchery wastes (V75 + B25) to evaluate their suitability. Ten kilograms of substrate and 6000 larvae composed each replicate (nine per group). Larvae were weighed and measured every two days until the 25% developed into prepupae. Larval mortality and growing indexes were calculated. Substrates, larvae, and frass chemical composition were analyzed. Larvae oxidative status and stability were measured in hemolymph and body. The V100 larvae showed the lowest live weight, length, thickness, and growth rate but had low mortality rate and high substrate reduction index and protein conversion ratio. The V100 larvae had similar protein to and lower lipids than the control ones, while the V50 + B50 and V75 + B25 larvae contained higher lipids and lower protein than the others. Despite the vegetable wastes, at different levels, the reactive oxygen species content decreased in hemolymph, and the V100 diet depressed growth performance and should be avoided. The use of butchery wastes combined with vegetable ingredients can be a suitable alternative to balance the high level of lipid and the low content of protein.

In vivo performances, ileal digestibility, and physicochemical characterization of raw and boiled eggs as affected by Tenebrio molitor larvae meal at low inclusion rate in laying quail (Coturnix japonica) diet.

A total of 120, twelve wk old female Japanese quails were divided into 4 groups (6 replicates of 5 birds each). The control group (CON) fed a corn-soybean diet; in the other 3 groups, Tenebrio molitor larvae meal (TML) replaced 5, 10, and 20% of the soybean protein (T5, T10, and T20). The laying performance and egg quality were studied for 54 d. The data were processed by a one-way ANOVA; the orthogonal contrast analysis was performed to test the linear, quadratic and cubic effects among the means. The laying rate and egg mass linearly decreased (P < 0.01) as the TML inclusion level in the diet increased. The egg weight and feed conversion ratio linearly increased from the control to T20 diet (P < 0.01) while the digestibility of dry matter, organic matter, and crude protein linearly decreased (P < 0.05). The albumen and yolk weight showed a linear increase (P < 0.01) due to dietary TML inclusion, while the eggshell weight showed the opposite (P < 0.05). The estimated activity of Δ9-desaturase (C16:0), Δ5+Δ6-desaturase on both polyunsaturated fatty acid n-6 and n-3 linearly increased (P < 0.05) as affected by dietary TML. The boiled yolk lightness (L*) showed higher values in T5 and T10 groups (quadratic contrast, P < 0.01). The yolk redness index (a*) showed lower values in T5 and T20 than control and T10 groups (cubic contrast, P < 0.01). The albumen L*, a*, and b* indexes showed a significant effect of the quadratic contrast (P < 0.05). In addition, the albumen b* index showed a significant effect of the cubic contrast (P < 0.01). The total lipids showed the highest values (cubic contrast, P < 0.05) in the T10 and T20 groups. The total monounsaturated fatty acids linearly increased (P < 0.05) according to the increase of dietary TML. The best inclusion level of defatted TML meal for laying quails seems to be 1.4% of diet, corresponding to the T5 diet.

Appetite Regulation, Growth Performances and Fish Quality Are Modulated by Alternative Dietary Protein Ingredients in Gilthead Sea Bream (Sparus aurata) Culture.

By answering the need for increasing sustainability in aquaculture, the present study aimed to compare growth, gene expression involved in appetite regulation, physical characteristics, and chemical composition of Sparus aurata fed alternative protein sources. Fish were fed ten iso-proteic, iso-lipidic, and isoenergetic diets: a vegetable-based (CV) and a marine ingredient-rich (CF) diet were set as control diets. The others were prepared by replacing graded levels (10, 20 or 40%) of the vegetable proteins in the CV with proteins from a commercial defatted Hermetia illucens pupae meal (H), poultry by-product meal (PBM) singly (H10, H20, H40, P20, P40) or in combination (H10P30), red swamp crayfish meal (RC10) and from a blend (2:1, w:w) of Tisochrysis lutea and Tetraselmis suecica (MA10) dried biomasses. The increase in ghre gene expression observed in MA10 fed fish matched with increased feed intake and increased feed conversion ratio. Besides, the MA10 diet conferred a lighter aspect to the fish skin (p < 0.05) than the others. Overall, no detrimental effects of H, PBM, and RC meal included in the diets were observed, and fish fatty acid profile resulted as comparable among these groups and CV, thus demonstrating the possibility to introduce H, PBM, and RC in partial replacement of vegetable proteins in the diet for Sparus aurata.

Use of chitosan and tannins as alternatives to antibiotics to control mold growth on PDO Pecorino Toscano cheese rind.

The fungal microbiota usually growing on the cheese surface during ripening processes promote rind formation and the development of organoleptic characteristics, imparting positive sensory attributes to cheeses. As cheese contamination may also occur by undesirable molds, specific actions for preventing their growth are usually realized in dairy industries by using the antibiotic natamycin, which may represent a risk factor for human health and environmental sustainability. Here, agroindustrial by-products with natural antimicrobial properties, i.e. tannins and chitosan, were tested in a cheese-making trial producing PDO Tuscan pecorino cheese. Morphological and molecular methods revealed that the main components of rind fungal communities of PDO Tuscan pecorino cheese were represented by P. solitum, P. discolour and P. verrucosum. The use of chitosan on cheese rinds did not significantly affect the composition of rind fungal communities developing during the whole ripening process compared with controls treated with natamycin, whose numbers ranged from 3.4 ± 1.3 × 103 to 3.2 ± 1.8 × 104 and from 6.3 ± 3.5 × 102 to 4.0 ± 1.5 × 104, respectively. Overall, grape marc tannins and chitosan did not significantly affect the number and composition of fungal communities developing during PDO Pecorino Toscano cheese ripening, as well as its physical, chemical and nutritional profiles, showing that they may represent effective alternatives to the antibiotic natamycin.

Quality of Eggs and Albumen Technological Properties as Affected by Hermetia Illucens Larvae Meal in Hens' Diet and Hen Age.

The impact on the egg quality and the albumen technological properties were here evaluated as affected by diet and hen age (A) of 162 Hy-line Brown hens. Three isoproteic and isoenergetic diets were formulated respecting the requirements for Hy-line hens: the control diet (C) based on conventional protein sources, and other two where vegetable proteins were substituted at 25% (HI25) and 50% (HI50) by partially defatted Hermetia illucens larva meal (HI). Ten eggs collected from each group at the hen ages of 20, 27, and 35 weeks were evaluated. The eggshell percentage and thickness were significantly reduced in the HI50 eggs (11.93% and 476 µm, respectively) compared to the C (12.34%, 542 µm) and HI25 (12.54%, 516 µm). The aging lowered (p = 0.05) the protein and increased (p < 0.001) water contents of the eggs. Although the foam capacity of the HI50 albumen was halved than the C group (p < 0.05), it was unaffected by the aging. Additionally, this did not impair the volume and the textural properties of a batter (angel cake) in which it was included. On the opposite, the textural characteristics of the cake made by the oldest hens (i.e., 35 wk-old) were compromised. In conclusion, the diet and hen age differently affected egg quality and its technological properties, which could be positive to obtain eggs to destine directly to the market or to the egg industry.

Total replacement of dietary fish meal with black soldier fly (Hermetia illucens) larvae does not impair physical, chemical or volatile composition of farmed Atlantic salmon (Salmo salar L.).

BACKGROUND: The aquafeed sector has been replacing conventional dietary ingredients with more economic and eco-friendly ingredients. Insects embody a promising alternative as a result of being highly nutritious and showing traits leading to a circular bioeconomy. Atlantic salmon (Salmo salar L.) at the sea-water stage were fed diets with a partial or complete substitution of fishmeal with meal of Hermetia illucens larvae reared on a media containing Ascophyllum nodosum mixed with organic wastes (60:40). The present study aimed to assess the quality of fillets by characterizing its physico-chemical traits with conventional and innovative methods, such as the proton transfer reaction-time of flight-mass spectrometer technique, allowing the analysis of samples at room temperature. Finally, steamed fillets underwent a consumer test to investigate the liking of consumers and their intention of re-consumption. RESULTS: The main findings showed that a complete dietary substitution of fishmeal with H. illucens larvae meal did not impair the physico-chemical quality of A. salmon fillets. Notably, neutral n-3 polyunsaturated fatty acids (PUFA) slightly but significantly increased in the fillets of A. salmon fed H. illucens, also as a result of the additional fish oil present in the diets containing insect. The volatile organic profile was not altered by the different diets. The consumer-liking test revealed that Italian consumers appreciated the tested salmon irrespective of the administered feed. CONCLUSION: Tailoring the insect fatty acid profile by rearing the larvae on a PUFA-rich substrate, coupled with a dietary modulation of the oily source, can successfully maintain or even increase the cardioprotective characteristics of fillets. © 2019 Society of Chemical Industry.

Mirrors Can Affect Growth Rate, Blood Profile, Carcass and Meat Traits and Caecal Microbial Activity of Rabbits Reared in a "Small Group" Free-Range System.

The aim of this work was to propose a model of free-range raising for rabbit able to maximize the animal welfare and at the same time the productive performances through the use of mirrors. A total of 81 rabbits were allocated into free-range areas and divided into three groups (nine replicates per group): in the first group (face to face, F2F), the rabbits of each replicate could see each other. In the second group (blind) each replicate was isolated from the others; in the third group (mirrors), the replicates were divided as for the Blind group but two mirrors were placed in a corner of the perimeter. The blind group rabbits showed the lowest final weight (p < 0.05), while rabbits from the mirrors groups showed the best FCR and net dressing out values. The blind group showed the highest production of total short chain fatty acids, acetate (p < 0.05) and propionate (p < 0.01). The F2F rabbits showed higher levels of creatine phosphokinase and lactate dehydrogenase and lower values of blood glucose than those of the other groups, due to the higher locomotion activity. The use of mirrors can improve rabbit's growth performance and carcass traits by lowering the rabbit's locomotion activity in comparison to the other tested systems.

Effect of Chestnut Tannins and Short Chain Fatty Acids as Anti-Microbials and as Feeding Supplements in Broilers Rearing and Meat Quality.

Chestnut tannins (CT) and saturated short medium chain fatty acids (SMCFA) are valid alternatives to contrast the growth of pathogens in poultry rearing, representing a valid alternative to antibiotics. However, the effect of their blends has never been tested. Two blends of CT extract and Sn1-monoglycerides of SMCFA (SN1) were tested in vitro against the proliferation of Clostridium perfringens, Salmonella typhymurium, Escherichia coli, Campylobacter jejuni. The tested concentrations were: 3.0 g/kg of CT; 3.0 g/kg of SN1; 2.0 g/kg of CT and 1.0 g/kg of SN1; 1.0 g/kg of CT and 2.0 g/kg of SN1. Furthermore, their effect on broiler performances and meat quality was evaluated in vivo: one-hundred Ross 308 male birds were fed a basal diet with no supplement (control group) or supplemented with CT or SN1 or their blends at the same concentration used in the in vitro trial. The in vitro assay confirmed the effectiveness of the CT and SN1 mixtures in reducing the growth of the tested bacteria while the in vivo trial showed that broiler performances, animal welfare and meat quality were not negatively affected by the blends, which could be a promising alternative in replacing antibiotics in poultry production.

Effects of three different stunning/slaughtering methods on physical, chemical, and sensory changes in rainbow trout (Oncorhynchus mykiss).

BACKGROUND: Electrical stunning (E) and asphyxia in the air (A) are two common stunning/killing methods for fish. However, they can stress the fish and affect flesh quality, so an alternative should be found. The present study aimed to evaluate the effects of carbon monoxide asphyxia (CO) compared to E and A on the evolution of post rigor mortis changes in rainbow trout (Oncorhynchus mykiss) fillets related to chemical, textural, and sensorial properties during storage time. RESULTS: Fish fillets from the E group showed a higher pH (P < 0.05) than the A ones, both at time of rigor resolution (TRR 0) and from TRR 4 until TRR 7 (7 days after rigor resolution, which corresponded to 10 days post mortem), with the CO group being always intermediate. The CO treatment ensured that the fillets showed the lowest yellowness index (b*), even if only at TRR 2 and TRR 5. Lipid oxidation and texture profile analyses were unaffected. Sensory analysis revealed that the CO fillets had the lowest odor intensity and the highest juiciness scores (P < 0.05). The sensory descriptors resulted the most discriminant variables of the fillets obtained from the differently stunned animals, as resulted by the canonical discriminant analysis. CONCLUSION: The carbon monoxide stunning/slaughtering method could be applied to rainbow trout without detrimental effects on physical, chemical, or sensory characteristics of the fish flesh. © 2018 Society of Chemical Industry.

Can the inclusion of black soldier fly (Hermetia illucens) in diet affect the flesh quality/nutritional traits of rainbow trout (Oncorhynchus mykiss) after freezing and cooking?

Physical and chemical parameters of rainbow trout fillets were tested during 120 days of frozen storage and following cooking. The fillets were obtained from rainbow trout-fed diets where dietary fishmeal was substituted with Hermetia illucens meal at 0, 25 and 50% inclusion levels, corresponding to control (C), Hi25, and Hi50 diets. Variations in quality traits of fillets emerged after 30 days of frozen storage, however they remained almost unchanged for the other 90 days. Increasing levels of H. illucens did not affect pH, shear stress, colour and water holding capacity of fillets. Saturated fatty acids were highly present in Hi50 samples, the polyunsaturated and some monounsaturated ones were higher in C than Hi50, whereas Hi25 always assumed intermediate contents in raw and cooked samples. A medium substitution at the 25% seemed to be the most practical application of insect meal in order to not modify too much the fillets characteristics.

Barbary partridge meat quality as affected by Hermetia illucens and Tenebrio molitor larva meals in feeds.

A partial substitution (25 or 50%) of dietary protein with Tenebrio molitor (TM) and Hermetia illucens (HI) meals as protein sources in the diet of Barbary partridge (Alectoris barbara) has been tested in terms of raw and cooked meat quality. Twelve partridges per feeding group (control - SBM, HI25, HI50, TM25 and TM50) were slaughtered. The peeled carcasses of the HI25, HI50, TM25 and TM50 groups were heavier than those of the SBM group, both raw and cooked. The pH, color and shear force of the raw meat were not affected to any greater extent by the diet, whereas the presence of insect meal seemed to increase the yellowness index of the cooked meat. The proximate composition was unaffected by both the species and the level of insect meal, although the fatty acid profile was changed considerably. The HI and TM groups had significantly higher C18:1n-9 and lower C16:0 contents than SBM. Furthermore, Hermetia illucens, added as 50% of the dietary protein, induced a significant increase in C12:0 and C16:1n-7. As a result, the highest AI and TI were obtained for the HI50 diet (0.38 and 0.75, respectively), whereas the TM groups both had intermediate AI values (around 0.35) and the lowest TI (0.67). Finally, the cholesterol content of the birds was not affected by insect inclusion in the feeds.

Effect of the housing system (free-range vs. open air cages) on growth performance, carcass and meat quality and antioxidant capacity of rabbits.

Growth performances and meat quality of free-range or cage raised rabbits were compared in 36 male animals. Rabbits were raised in free-range areas (2000 cm2/head) or in open-air cages (800 cm2/head) from weaning to 99 days old. Daily weight gain and final live weight were higher (P < 0.05) for the rabbits raised in cages which presented a more favourable feed conversion ratio (P < 0.05) than in the free-range group. The average feed intake, liver and empty gastro-intestinal tract weights were higher (P < 0.05) in the free-range group, while the interscapular fat percentage was higher (P < 0.05) in the caged rabbits. Loins of free-range rabbits had higher amount of PUFA n-6 in neutral lipids (P < 0.05) whereas their polar lipids were richer in PUFA n-6 and n-3 than in those of the cage group. Muscular fat of free-raised rabbits was found to be less susceptible to be oxidized, having a higher antioxidant capacity than the caged group.

Carbon monoxide as stunning/killing method on farmed Atlantic salmon (Salmo salar): effects on lipid and cholesterol oxidation.

BACKGROUND: Carbon monoxide (CO) has been recently utilized as a new stunning/killing procedure for Atlantic salmon (Salmo salar). Its effects on lipid and cholesterol oxidation of farmed Atlantic salmon fillets were evaluated at two times of refrigerated (2.5 °C) storage, T0 (64 h after death) and T14 (14 days from T0). The use of CO was compared with the commonly utilized percussion (P) method. RESULTS: Fatty acid profile, primary (conjugated dienes) and secondary (TBARS) oxidation products, cholesterol oxidation products (COPs) and carotenoids were unaffected by the killing method. Despite the low oxidative status of lipid (0.66 and 0.60 mg malondialdehyde kg(-1) muscle in P and CO fish respectively), cholesterol was found to be highly oxidized (0.17 and 0.13 mg COPs kg(-1) ). Storage significantly affected oxidative stability of fish muscle by increasing oxidation products. Interestingly, TBARS content doubled while the increase for COPs was not homogeneous: α- and ß-epoxycholesterol increased by 25%, whereas triol and 7-ketocholesterol increased by 48 and 62% respectively. CONCLUSION: The quality of salmon fillets just after slaughtering and after 14 days of refrigerated storage at 2.5 °C did not change, irrespective of the killing method adopted, suggesting that the CO method may be applied without any detrimental effect on the quality of fish fillets. © 2015 Society of Chemical Industry.