Caracterización del perfil lipídico de la grasa abdominal y molleja de pollos parrilleros J. Food Sci. Gastron . (July - December 2023) 1(2): 7-12https://doi.org/10.5281/zenodo.13994670ISSN: 3073-1283 ORIGINAL ARTICLE Characterization of the lipid profile of abdominal and gizzard fat of broiler chickens Yanelis Ruiz yanelis.ruiz@ug.uchile.cl1 Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago de Chile, Chile.2 Departamento de Ciencias Exactas, Universidad de las Fuerzas Armadas ESPE, Sede Santo Domingo, Ecuador.Received: 10 March 2023 / Accepted: 23 June 2023 / Published online:15 July 2023© The Author(s) 2023 Yanelis Ruiz 1 · Nahir Y. Dugarte 2 Abstract It evaluated the infuence of the diet on the lipidic profle of abdominal and gizzard fat of broiler chickens from farms with diferent climatic conditions. For determining the fatty acids of gizzard and abdomen samples it was used 300 g of fat (60 % abdominal and 40 % of gizzard). The color of solid and fused chicken fats was determined through the chromatic coordinates of the system CIE-L*a*b*. No signif-icant diferences existed ( p ≤0.05) among the lipid profles of the pieces of chickens, which is related to the stability of the feeding that the poultry received in each one of the farms. Palmitic and oleic acids were the majority of fatty acids in the chicken fat. Keywords chicken fat; lipid profle; animal nutrition. Resumen Se evaluó la infuencia de la dieta en el perfl lipídico de la grasa abdominal y de la molleja de pollos pa-rrilleros provenientes de granjas con diferentes condiciones climáticas. Para la determinación de los ácidos grasos de muestras de molleja y abdomen se utilizaron 300 g de grasa (60 % abdominal y 40 % de molleja). Se realizó la evalua-ción del color a las grasas de pollo sólida y fundida a través de las coordenadas cromáticas del sistema CIE-L*a*b*. No existieron diferencias signifcativas ( p ≤0,05) entre los perf-les lipídicos de las canales de pollos, lo cual está relacionado con la estabilidad de la alimentación que recibieron las aves en cada una de las instalaciones. Los ácidos palmítico y olei-co fueron los ácidos grasos mayoritarios de la grasa de pollo. Palabras clave grasa de pollo, perfl lipídico, nutrición ani-mal. How to cite Ruiz, Y., & Dugarte, N.Y. (2023). Characterization of the lipid profle of abdominal and gizzard fat of broiler chickens. Journal of Food Science and Gastronomy , 1 (2), 7-12. https://doi.org/10.5281/zenodo.13994670
J. Food Sci. Gastron . (July - December 2023) 1(2): 7-12 8 Introduction In Chile, the poultry industry has experienced signif-cant growth in recent decades, positioning itself as one of the main producers and consumers of chicken meat in Latin America. According to reports, per capita chicken meat con-sumption in Chile has increased signifcantly, with an av-erage of 24.03 kg of poultry consumed per person in 2020, refecting a growing trend towards chicken as a protein source in the Chilean diet. Additionally, poultry meat pro-duction has maintained an annual growth rate of 7.6% over the last decade, evidencing strong demand both nationally and internationally. Chile is among the six largest chicken meat producers in the region and is the third largest exporter, highlighting the importance of this industry for the country’s economy (Gutiérrez, 2020).The content and composition of lipids in chicken meat are infuenced by various factors, including genetics, age, sex, environmental conditions, and nutritional aspects. Nutrition-al factors, in particular, play a fundamental role, emphasiz-ing the energy and lipid and protein composition of the diet. According to Mir et al. (2017), the variation in the quality of chicken meat can be attributed to these factors, which afect not only the amount of fat but also the proportion of fatty acids present in muscle tissue. In recent decades, research in animal nutrition has focused its eforts on improving the nutritional value of animal products to meet consumer de-mands for healthier foods with longer shelf lives (Choi et al., 2023). Specifcally, poultry meat, being a monogastric animal, contains a high percentage of polyunsaturated fatty acids, making it susceptible to modifcations through difer-ent nutritional strategies (Cartoni et al., 2022).Abdominal fat in slaughtered chickens represents between 2% and 2.5% of their total weight (Santos et al., 2020). This fat has great potential as an ingredient in the production of sausages, as it contains high concentrations of oleic, palmit-ic, and linoleic acids. However, small producers often dis-card it, along with ofal, feathers, and blood, generating a negative environmental impact.In recent years, consumers have become more aware of the infuence of diet on their health, leading to a shift in eating habits, especially regarding the quantity and type of fats con-sumed. Current dietary recommendations promote reducing saturated fat intake and increasing polyunsaturated fats, as the latter has been shown to have benefcial efects in pre-venting cardiovascular diseases and cancer. It has been sug-gested that diets should obtain more than 30% of their total energy from polyunsaturated and monounsaturated fatty ac-ids, limiting saturated fatty acid intake to a maximum of 10% (Ros et al., 2015). The objective of this study was to evaluate the infuence of diet on the lipid profle of abdominal fat and the gizzard of broiler chickens. Materials and methods To evaluate the infuence of diet on the lipid profle of ab-dominal fat and the gizzard, broiler chickens were selected from three farms (A, B, and C) in the Libertador Bernardo O’Higgins Region. For ethical reasons, the names of these farms are not disclosed. The animals had ad libitum access to food and water. Additionally, an analysis of the composition of the feed provided at each of the farms was conducted.To determine the fatty acids in the samples of abdominal fat and gizzard, 300 g of fat (60% abdominal and 40% giz-zard) were used. The extraction of fats and fatty acids was performed using the Soxhlet method, utilizing diethyl ether. Subsequently, the fats were methylated to form fatty acid methyl esters (FAME), which were quantifed by gas chro-matography, using C11:0 methyl ester as an internal stan-dard. The total fat content was estimated by summing the individual fatty acids, expressed as triglycerides (Prosser et al., 2010).The color analysis of the fat samples was performed us-ing an X-RITE spectrophotometer, measuring the CIE-Lab* coordinates in 30 fat samples at diferent points on their sur-face. Results and discussion The lipid deposition in animal tissues had two origins: ex-ogenous, coming from the diet (Table 1), and endogenous, synthesized de novo by the animal. The type of lipid depo-sition depended on the balance between the exogenous and endogenous lipid portions. It has been observed that the in-clusion of fat in the diet reduced hepatic lipogenic activity, establishing a balance between exogenous contribution and endogenous lipid synthesis, which kept the total lipid content of the animal relatively constant (Duarte et al., 2014).This reduction in endogenous lipogenesis resulted, on one hand, from a lower starch content in the diet due to the inclu-sion of fat, which reduced the substrate for fatty acid synthe-sis; and on the other hand, from direct inhibition of lipogenic enzymes by dietary lipids (Saponaro et al., 2015). Thus, he-patic lipogenesis increased when dietary energy came from carbohydrates and decreased with the addition of lipid sourc-es (Carvajal, 2015; Hernández-Rodas et al., 2016).Several studies supported the possibility of modifying the proportion of fatty acids in chicken meat through feeding to obtain healthier profles. In this regard, the incorporation of sunfower and corn oils, rich in oleic acid, into the diets in-creased the monounsaturated fatty acids in the fnal product. When low-fat diets were administered to the birds, most of the fatty acids in their tissues came from de novo synthesis from carbohydrates (Gallardo et al., 2012). The main fatty acids resulting from endogenous synthesis were saturated
J. Food Sci. Gastron . (July - December 2023) 1(2): 7-12 9 fatty acids, such as palmitic (C16:0) and stearic (C18:0) ac-ids, and monounsaturated fatty acids, such as oleic (C18:1, ω-9) and palmitoleic (C16:1, ω-7) acids (Ferreri et al., 2020).Additionally, the use of soy in the diet decreased the pro-portion of saturated fatty acids and improved the ω-6/ω-3 ratio in the lipids of the meat. Some studies have evaluated the use of diferent sources rich in specifc fatty acids in the diets of animals to produce chicken meat with a higher con-tent of these fatty acids (Attia et al., 2020). The content of saturated fatty acids increased with the inclusion of coconut oil (Piracicaba et al., 2009) or palm oil, while the content of oleic acid increased with olive, sunfower, corn, and soy oils (Andreotti et al., 2001). Table 1. Formulation of the fattening feed for chickens in the selected farms. IngredientFormulation (%)12345 Sorghum10.010.010.010.010.0Soybean oil3.203.503.754.004.1Yellow corn10.010.0010.010.0010.0White corn44.544.2545.044.9045.05Corn gluten4.44.754.64.204.15Bone meal3.03.12.953.203.25Soybean meal11.2511.0015.014.814.6Roasted soybeans10.010.04.05.15.05Table 2 presents the lipid profle of the feed used in the farms. No diferences were observed in the total fat content between the evaluated diets, although there was variation in the percentages of the ingredients. The predominant fatty acids in the feed were linoleic, oleic, and palmitic, with av-erage values of 52.1%, 25.08%, and 11.27%, respectively. Table 2. Lipid profle of the fattening feed for chickens in the selected farms. Fatty acids (%) Fattening feed 1234 5 C≤14 (Others)0.00.00.00.00.0C14:0 (Myristic acid)0.190.180.160.150.15C16:0 (Palmitic acid)11.511.311.211.111.25C16:1 (Palmitoleic acid)1.050.951.01.01.02C18:0 (Stearic acid)4.13.93.853.954.0C18:1 (Oleic acid)25.0525.125.025.1525.1C18:2 (Linoleic acid)52.152.252.1552.052.05C18:3 (Linolenic acid)5.65.55.455.555.5C≥19 (Others)0.680.70.690.710.7Total fat in the diet (%)7.527.497.467.467.52The formulation of the fattening feed for chickens on the farms directly infuenced the lipid profle. It is observed that soybean oil, an important source of lipids, progressively increases in the formulation, from 3.2% in the frst feed to 4.1% in the ffth formulation. This variation is consistent with the levels of polyunsaturated fatty acids, such as lin-oleic acid (C18:2), which maintains a stable and high value between 52.0% and 52.2%, aligned with the greater propor-tion of soybean oil, which is rich in this fatty acid. Likewise, linolenic acid (C18:3), although with small variations, is also related to this source of vegetable lipids.
J. Food Sci. Gastron . (July - December 2023) 1(2): 7-12 10 On the other hand, soybean meal, another key source of lipids, experienced an increase in formulations 3, 4, and 5 (up to 15%), which could infuence the levels of unsaturat-ed fatty acids, such as oleic acid (C18:1), which remained constant (25.0 - 25.15%). Finally, the stability of the total fat in the diet (7.46 - 7.52%) reinforces the consistency in the formulation of the feed, with minor adjustments that do not alter the lipid profle of the feed.Animal fat deposits largely come from the diet, and the fatty acid profle in the tissues refects that of the diet. Table 3 shows the lipid profle of the carcasses of the studied birds. There were no signifcant diferences ( p >0.05) between the lipid profles of chickens from the diferent farms, which was related to the stability of the feeding they received (Tables 1 and 2). Table 3. Lipid profle of chicken carcasses from the selected farms (n = 30) Lipid profle Farms Variation coefcient (%) ABC Palmitic acid (%)18.017.517.941.25Oleic acid (%)27.026.027.21.96Linoleic acid (%)17.517.016.831.66Saturated fat (%)23.522.023.062.75Unsaturated fat (%)51.050.052.622.11Monounsaturated fat (%)32.531.033.22.85Polyunsaturated fat (%)18.018.218.651.49Omega 3 (mg/100 g)1100115011622.36Omega 6 (mg/100 g)1710017200173350.56Omega 9 (mg/100 g)2870026700299844.75It was observed that the bird fat contained a higher per-centage of unsaturated fats (51.2%) compared to saturated fats (23.3%), which coincided with the diet received. Addi-tionally, the fat presented an adequate amount and propor-tion of fatty acids from the ω-6 and ω-3 families (Ros et al., 2015).Abdominal fat could be used as an ingredient in sausage production due to its high concentration of oleic, palmitic, and linoleic acids. Reports have indicated proportions of saturated, monounsaturated, and polyunsaturated fatty ac-ids that varied between 29-35%, 47-57%, and 10-24%, re-spectively, depending on the analyzed fat sample. The low amount of saturated triglycerides (<3%) was a consequence of the low concentration of solid fat at room temperature (3-10% at 20 °C). The predominant fatty acids in chicken fat were palmitic and oleic, which aligned with the results of this research.According to the study by Ming et al. (2002), chicken fat contained about 60% unsaturated fatty acids, making it more unsaturated than beef tallow. Monounsaturated fatty acids, such as oleic acid, were considered benefcial for the pre-vention of coronary diseases. Chicken fat was recognized as an important source of monounsaturated fatty acids, with concentrations ranging from 45% to 50%, in contrast to beef tallow, which contained between 30% and 40%. Monounsat-urated fatty acids helped reduce cholesterol levels in certain individuals with normal triglyceride levels, and it was rec-ommended that these fatty acids represent half of the calories coming from the lipid fraction of the diet.The high activity of oleins in the abdominal fat of chick-ens suggested that it could be used as frying oil or mixed with solid fats to increase its plasticity. Furthermore, its high oleic acid content allowed its use as a dietary supplement of monounsaturated fatty acids or in the production of lipid structures (Ming et al., 2002). The results of the instrumental color analysis of solid and melted chicken fat are shown in Table 4. Table 4. Chromatic coordinates of melted and solid chicken fats (n = 30) SampleL*a*b*C*h° Melted fat40.51.066.066.089.5Solid fat71.03.525.025.082.0
J. Food Sci. Gastron . (July - December 2023) 1(2): 7-12 11 The analysis of the chromatic coordinates of chicken fat reveals signifcant diferences between its melted and solid states, which infuence sensory attributes such as color and should be considered in the formulation of products like sau-sages. The solid fat presents a high luminosity value (L*) of 71.0, indicating a lighter color compared to the melted fat, which has an L* value of 40.5, refecting a darker color. This dif-ference in luminosity may be related to the structure of the lipids in the solid state, which retain less color, while in the melted state, compounds are released that tend to darken the product. Regarding the b* component, which measures the inten-sity of yellow-blue tones, the melted fat has a signifcantly higher value (66.0) than the solid fat (25.0). This indicates that the melted fat takes on a more pronounced yellow hue due to the greater oxidation of unsaturated fatty acids during heating. This color diference should be taken into account in sausage production, where the percentage of fat used will directly afect the sensory perception of the color of the fnal product, particularly if melted or solid fat is chosen.Therefore, using chicken fat as an ingredient in the for-mulation of processed meat products, whether melted or solid, will infuence its color, a key attribute for consumer acceptance, depending on the percentages and types of fat employed in the product formulation. Conclusions There were no signifcant diferences ( p ≤0.05) between the lipid profles of the carcasses of chickens from the diferent processing farms, which is related to the stability of the feed-ing received by the birds in each of the facilities. Palmitic and oleic acids were the predominant fatty acids in chicken fat . References Andreotti, M.O., Junqueira, O.M., Cancherini, L.C., Rodri-gues, E.A., & Sakomura, N.K. (2001). Valor nutricional de algumas fontes de gordura para frangos de corte. In: Anais da 38° Reunião Anual da Sociedade Brasileira de Zootecnia. Piracicaba: SBZ.Attia, Y.A., Al-Harthi, M.A., & El-Maaty, H.M.A. (2020). The efects of diferent oil sources on performance, digestive enzymes, carcass traits, biochemical, immu-nological, antioxidant, and morphometric responses of broiler chicks. Frontiers in Veterinary Science, Section Animal Nutrition and Metabolism , 7 , 181. https://doi.org/10.3389/fvets.2020.00181 Cartoni, A., Mattioli, S., Twining, C., Dal Bosco, A., Dono-ghue, A.M., Arsi, K., Angelucci, E., Chiattelli, D., & Castellini, C. (2022). Poultry meat and eggs as an al-ternative source of n-3 long-chain polyunsaturated fat-ty acids for human nutrition. Nutrients , 14 (9), 1969. https://doi.org/10.3390/nu14091969Carvajal, C. (2015). Tejido adiposo, obesidad e insulino re-sistencia. Medicina Legal de Costa Rica , 32 (2), 138-144.Choi, J., Kong, B., Bowker, B.C., Zhuang, H., & Kim, W.K. (2023). Nutritional strategies to improve meat quality and composition in the challenging conditions of broil-er production: a review. Animals (Basel) , 13 (8), 1386. https://doi.org/10.3390/ani13081386Duarte, J.A., Carvalho, F., Pearson, M., Horton, J.D., Brown-ing, J.D., Jones, J.G., & Burgess, S.C. (2014). A high-fat diet suppresses de novo lipogenesis and desaturation but not elongation and triglyceride synthesis in mice. Journal of Lipid Research , 55 (12), 2541-2553. https://doi.org/10.1194/jlr.M052308Ferreri, C., Sansone, A., Buratta, S., Urbanelli, L., Costanzi, E., Emiliani, C., & Chatgilialoglu, C. (2020). The n-10 Fatty Acids Family in the Lipidome of Human Prostat-ic Adenocarcinoma Cell Membranes and Extracellular Vesicles. Cancers (Basel) , 12 (4), 900. https://dx.doi.org/10.3390/cancers12040900Gallardo, M.A., Pérez, D.D., & Leighton, F.M. (2012). Mod-ifcation of fatty acid composition in broiler chickens fed canola oil. Biological Research , 45 (2), 149-161. https://dx.doi.org/10.4067/S0716-97602012000200007Gutiérrez, M.A. (2020). En Chile, el consumo de carne de pollo lidera entre las carnes. Avinews. https://avinews.com/chile-consumo-carne-pollo-lidera-entre-carnes/Hernández-Rodas, M.C., Morales, J., Valenzuela, R., Mo-rales, G., & Valenzuela, A. (2016). Benefcios de los ácidos grasos poliinsaturados de cadena larga n-3 en la enfermedad por hígado graso no alcohólico. Revis-ta Chilena de Nutrición , 43 (2), 196-205. https://dx.doi.org/10.4067/S0717-75182016000200013Ming, C.C., Gioielli, L.A., & Sotero, V. (2002). Fraccio-namiento de la grasa abdominal de pollo. Grasas y Aceites , 53 (3), 298-303.Mir, N.A., Rafq, A., Kumar, F., Singh, V., & Shukla, V. (2017). Determinants of broiler chicken meat quality and factors afecting them: a review. Journal of Food Science and Technology , 54 (10), 2997-3009. https://doi.org/10.1007/s13197-017-2789-z
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