Functional meat and meat products from unconventional meat species

The present thesis, which includes four main researches, aimed to study functional meat and meat products obtained from unconventional meat species, namely the rabbit and the ostrich. The first research tested the single and combined dietary supplementation with 5% Spirulina (Arthrospira platensis) and 3% Thyme (Thymus vulgaris) to growing rabbits for 3 and 6 weeks, and it is articulated in four different subchapters. The first subchapter considered the effect on total tract apparent digestibility of nutrients and on the performances of growing rabbits and showed that that single and combined supplementation with Spirulina reduced the nutritive value of the diets. Despite this, no substantial effect on growth performance and health status, was observed. Future studies should take into consideration feed processing technology, pelleting, storage and packaging conditions, as they may reduce or nullify the nutrient and functional compounds’ availability. Moreover, Spirulina and/or Thyme effect on health status should be tested under poorer sanitary conditions. The second subchapter studied the effects on growing rabbit carcass composition, meat and bone rheological traits, and the vitamin B12 content of Longissimus dorsi (LD) meat. Spirulina was confirmed as a rich source of vitamin B12 that was successfully transferred into LD meat, thus demonstrating its value as an effective natural supplement in producing food fortified with this vital element. With this exception, the supplement as well as and the duration of treatment had no effect on the considered traits. The third subchapter evaluated the effect on rabbit meat during retail display. Thyme improved colour parameters and reduced exudative losses during a simulated retail display, also considering a shorter supplementation period. This would positively impact consumers at the time of purchase as well as farmers demand to limit production costs. Differently, Spirulina had no effect on oxidative stability of rabbit meat, maybe for the poor absorption from the gut as a result of interference on uptake of antioxidants by Spirulina, or maybe because dietary level of Spirulina was not adequate for rabbits requirements. The fourth subchapter studied the effects on raw and cooked rabbit meat quality, nutrient true retention and protection against oxidative stress conditions. The dietary inclusion of Spirulina improved the FA profile of the Longissimus dorsi and hind leg meat by significantly increasing γ-linolenic acid content. Thyme improved the oxidative stability of raw and freeze-dried HL meat but not that of cooked meat. As for the shelf-life trial, Spirulina was not observed to improve the oxidative stability of rabbit meat subjected to severe oxidative stress. The second research of the present thesis, aimed to evaluate the effect of the dietary single or combined supplementation with different natural additives (Oregano, Rosemary, vitamin E and Saccaromyces cerevisiae) on the performance of growing rabbits, the nutritional composition and oxidative stability of their meat and on their hind leg bone traits. The results of this research demonstrated that an adequate supplementation with natural antioxidants can also have a positive effect on productive performance and meat quality. The fifth chapter evaluated, for the first time, the unfermented and fermented rooibos (Aspalathus linearis) in preventing lipid oxidation in ostrich meat patties and ostrich salami. This plant showed interesting and promising antioxidant potential when applied to meat products, even if further study are necessary to deeply investigate long-term effects. The sixth chapter studied the effect of two different fat inclusion levels, NaCl contents and two LAB starter cultures on the weight loss, proximate composition and cholesterol content of ostrich salami ripened for 10 and 20 weeks. A lower fat content consistently shortened ripening time, thus being a positive aspect in terms of productivity, and it determined a higher nutrients concentration compared to high fat salami. Reducing the NaCl inclusion, retarded the weight loss of the product of about 1 week, without affecting its proximate composition. Finally, the metabolic activity of tested LAB starter cultures seemed to be influenced by the fat inclusion level, ultimately affecting the healthiness of the products at 10 weeks of ripenin

Meat quality of male and female Italian Padovana and Polverara slow-growing chicken breeds

The study characterised and compared proximate composition and fatty acid (FA) profile of breast and leg meat of chickens belonging to Padovana and Polverara Italian local breeds. Birds were slaughtered at 183 days of age and four experimental groups were formed: Padovana males (PAD M), Padovana females (PAD F), Polverara males (POL M) and Polverara females (POL F). Proximate composition was assessed on 10 breasts and 10 legs per group, whereas FA profile and cholesterol content were assessed on six samples per cut per group. Breast meat proximate composition resulted in similarity between the two genotypes and sexes. Genotype did not affect breast FA profile except for C18:1 n-11, whereas females breast meat was richer in DHA (p < .05) and thus in n-3 (p < .05). Leg meat exhibited greater variability due to genotype and sex. Indeed, PAD chicken legs were richer in dry matter (p < .01), lipids (p < .01) and cholesterol (p < .01) than POL. It emerged that leg meat from PAD breed was characterised by a more desirable FA profile due to its higher UFA:SFA (p < .05) and lower n–6/n–3 (p < .05) ratios. Despite exhibiting a lower PUFA:SFA ratio than males (p < .05), females exhibited a better n–6/n–3 ratio (p < .01). The two genotypes and the two sexes possess peculiar nutritional quality. The aim of this study was to create economic interest around these local productions to assure their survival.Highlights Padovana and Polverara are two rustic slow-growing chicken breeds which are farmed in the Veneto region of Italy. The goal of the present study is contributing to the creation of economic interest around local productions from Padovana and Polverara chickens. Creating an economic interest around Padovana and Polverara breeds would contribute to the preservation of local tradition and rural culture

Effect of "wooden breast" appearance on poultry meat quality, histological traits, and lesions characterization

The purposes of the study were to investigate the effects of Wooden Breast (WB) myodegeneration on poultry meat quality and to give a contribution in typing lesions morphology. At a poultry meat cutting facility, 474 carcasses of a high-breast-yield hybrid chickens were inspected for WB condition, and 30 normal (N) and 30 affected (WB) breast fillets (Pectoralis major) were randomly selected. The WB condition represented 53.2% of the examined carcasses. Weight, cross sectional area (CSA), pH, L*, a*, b* colour values, water-holding capacity, and Warner-Bratzler shear force were determined. Samples were also visually and histologically evaluated. Affected samples were heavier, thicker, paler (P < 0.001), and characterized by palpatory hardness and lower water holding capacity (P < 0.05). Macroscopically, abnormalities were primarily localized in the cranial portion of the fillet and defined by the presence of bulges, petechiae, fluid and clear exudate, and higher pH. Microscopically, the WB condition was characterized by muscle fibres with greater CSA (P < 0.001) and higher giant fibres prevalence (P < 0.01). Data suggest a relationship between breast weight and WB condition

Productive performances and carcase quality of male and female Italian Padovana and Polverara slow-growing chicken breeds

Live performances and carcase quality of Padovana (n = 81) and Polverara (n = 76) chickens were investigated considering breed, gender and their interaction (B × G). Birds were reared until 183 d of age. After slaughter, yields were computed, and pH and L*a*b*colour values were measured on breast and leg meat. Breeds exhibited similar performances and yields, except a greater commercial carcase incidence for Polverara (p < .01). Breast meat quality was similar, except for higher L* value of Padovana fillets (p < .01). Polverara legs exhibited lower pH (p < .0001), lower L* value (p < .001) and higher a* value (p < .0001). Gender influenced performances and carcase quality traits. Males showed heavier live weight (p < .0001), carcase weight and cuts (p < .0001) and commercial carcase yield (p < .05), females displayed greater breast yield (p < .0001), whereas net carcase yield (% SW) was similar between sexes. Female fillets showed lower pH (p < .001) and higher L* and b* values (p < .0001); their legs had also higher L* and b* values (p < .0001). On the contrary, male legs were remarkably redder (p < .0001). Considering breast meat quality, B × G interaction counterposed Polverara males and Polverara females, whereas the greatest differences in leg meat quality existed between Polverara males and Padovana females. This study revealed that the two breeds and genders possess peculiar quality traits

Potentiality of protein fractions from the house cricket (Acheta domesticus) and yellow mealworm (Tenebrio molitor) for pasta formulation

House cricket (Acheta domesticus; AD) and yellow mealworm (Tenebrio molitor; TM) are two promising insect species for possible novel food applications. In this research the insect protein fractions were extracted, characterised, and used in the manufacturing of pasta by replacing semolina with 14% of powdered proteins. Pasta samples were then analysed to evaluate technological quality aspects. Results showed that insect protein inclusion resulted in a darker (L* value: 76.7, 53.4, 59.9 for control, AD and TM, respectively) and firmer (12.4, 13.7, 13.8 N: control, AD and TM, respectively) AD and TM pasta, and a higher water absorption index for AD (148, 178, 150%: control, AD and TM, respectively). In conclusion, both extracts offer interesting opportunity for pasta formulations, possibly leading to an improved protein content and quality. From an industrial perspective, the present study demonstrated that the tested edible insects can provide protein extracts for the possible fortification of pasta with high-quality protein and technological traits, thus representing an ingredient with interesting potential for several food applications

Effect of dietary supplementation with full-fat silkworm (Bombyx mori L.) chrysalis meal on growth performance and meat quality of Rhode Island Red × Fayoumi crossbred chickens

The objective was to study the effect of the partial substitution of soybean meal and oil with full-fat silkworm (Bombyx mori L.) meal (SWM) in the diet of growing chickens, on their growth and meat quality traits. A total of 195 1-day-old chicks of both sexes were allocated to 15 littered floor pens and assigned to three dietary treatments (5 replicates/treatments) until 8 weeks of age: a commercial diet (Control) and other two diets with an inclusion of either 25% (SWM25) or 50% (SWM50) SWM. At 8 weeks of age, two males/replicates were slaughtered and carcases dissected to compute yields. Pectoralis major muscle was subjected to pH and L*a*b* colour values, proximate composition and fatty acid profile analysis. All chickens showed satisfactory growth performance throughout the trial, with the best growth being observed in the SWM25 group. Carcase traits remained unaffected by the dietary treatment, but SWM25 chickens had a higher breast yield (p < .05) than the Control group. The pH of SWM50 breasts was higher than Control (p < .01). Dietary treatments affected meat protein content, differing between SWM25 and SWM50 (22.2 versus 23.3%, respectively; p < .05). SWM dietary inclusion increased n-3 PUFA and lowered the n-6 PUFA proportions in a level-dependent manner. Consequently, n-6/n-3 ratio diminished, thus improved, with the dietary SWM inclusion. Results showed that it is possible to partly substitute soybean meal/oil with SWM in the diet of chickens, ensuring satisfactory performance and carcase traits, and providing meat with a healthier n-6/n-3 ratio.Highlights Silkworm (Bombyx mori) chrysalis is a possible sustainable feed ingredient for growing chickens, alternative to conventional soybean. The dietary inclusion of silkworm full-fat meal in chicken diets provided satisfactory growth performance, carcase and meat quality traits. The dietary inclusion of full-fat silkworm meal in chicken diets enriched meat lipids with omega-3 fatty acids

Camelina sativa as a sustainable and feasible feedstuff for laying poultry: A review

Camelina sativa is a promising oilseed crop with unique characteristics, including rapid growth, drought and frost tolerance, low input requirements, and resistance to pests and diseases. It offers diverse applications in both feed and non-feed sectors, primarily due to its high levels of n-3 polyunsaturated fatty acids (PUFA) and antioxidants. However, the presence of secondary plant metabolites in camelina restricts its use in poultry nutrition. These compounds may inhibit some digestive enzymes, increase digesta viscosity, and affect nutrients absorption, potentially compromising bird health and product quality. Various techniques, such as heat treatment, multi-enzyme supplementation, and copper supplementation, have been employed to mitigate the negative effects of these antinutritional compounds. Inclusion at high levels (>10%) of camelina by-products in poultry diets has been found to decrease nutrients digestibility and laying performance. Nonetheless, the inclusion of camelina by-products, particularly oil, in the diets resulted in comparable or improved egg quality. The egg yolk fatty acid profile exhibited a higher content of PUFA, reducing the n-6/n3 ratio, thereby enhancing the nutritional value of eggs. Sensory evaluations showed no significant differences in product quality among diet groups. This review highlights the feeding value of camelina by-products and provides a comprehensive overview of the existing literature, focusing on digestibility, performance, and egg quality evaluation in laying poultry diets

Research Note: Effect of chicken genotype and white striping–wooden breast condition on breast meat proximate composition and amino acid profile

The present experiment compared the proximate composition, the amino acid content, and profile of the breast meat of a commercial broiler hybrid (Hybrid-Normal) vs. a broiler hybrid affected by the simultaneous presence of white striping (WS) and wooden breast (WB) myopathies (Hybrid-WSWB) vs. the Italian purebred Polverara chicken (Polverara). To this purpose, a total of n = 30 breast meat cuts from male chickens/group were subjected to meat quality evaluations. Chickens were slaughtered at their commercial age. The meat of the Polverara breed showed the highest protein (P < 0.0001) and the lowest lipids (P < 0.0001) contents, whereas that of the Hybrid-WSWB broiler chickens had the lowest protein and ash (P < 0.0001) contents and the highest (P < 0.0001) amount of fat. Meat of Hybrid-Normal chickens displayed intermediate values. Polverara meat was the richest in most amino acids (g/100 g meat), whereas Hybrid-WSWB one had the lowest content (P < 0.0001). Taurine was not detected in the meat of the Polverara chicken. The meat of Hybrid-Normal chickens was the richest in valine and taurine amino acids (P < 0.0001). Results on the amino acids proportions (% of total amino acids) highlighted that lysine, arginine, leucine, glutamic acid, aspartic acid, alanine, and serine were the most representative essential and nonessential amino acids, respectively, in all 3 meat-types chickens. The study confirmed that WS and WB myopathies negatively affect the meat proximate composition and the amino acid content. The meat of the Polverara breed displayed a remarkable meat quality including a high protein content of very good quality. This may represent a tool to promote its meat among consumers and help the survival of this endangered breed. Furthermore, research efforts should be conducted to understand why taurine was absent in the breast meat of Polverara chicken

Effect of Digestarom® Dietary Supplementation on the Reproductive Performances of Rabbit Does: Preliminary Results

The study investigated the effect of Digestarom® dietary supplementation on the reproductive performances of rabbit does. Pannon Ka (maternal line) multiparous does were randomly divided into two dietary groups since insemination and fed ad libitum. In the first group (n=51), rabbit does were fed with a commercial diet (C), whereas in the other group (n=52) they received the same diet supplemented with 300 mg/kg of Digestarom® (D). The experiment lasted for two reproductive cycles (kindling 1=K1; kindling 2=K2). Body weight of does and litter size (kits born total, alive, stillborn) were recorded at kindling. Litter size and litter weight were registered at 7, 14, 21 days of age after nursing, and the average individual weight of kits was calculated. Kits' mortality was recorded daily. At K1, rabbit does performances were unaffected by dietary treatments. During K2, D does were significantly lighter than C ones (P<0.05) and displayed a lower kindling rate (P<0.05). Digestarom® did not improve the reproductive performance of rabbit does. They seemed to dislike the D diet in K1 and such behavior could have led to the negative results in K2. Further studies should focus on feed acceptance, dose-dependent effect, physiological adaptation and in vivo oxidative status of does. Finally, several consecutive reproductive cycles are recommended to test the efficacy of new feed supplements