Citric acid in the diet of male Venda chickens: Effects on carcass characteristics and physico-chemical attributes

 

 

M.V. Mamabolo; J.W. Ng'ambi; B. Gunya

Department of Agricultural Economics and Animal Production, University of Limpopo, Private Bag X1106, Sovenga 0727, South Africa

 

 

---

ABSTRACT

This experiment was conducted to determine the effects of citric acid (CA) on carcass characteristics and physico-chemical attributes of male Venda chickens. A total of 200 male, one-day-old Venda chicks were distributed in a completely randomized design with four treatments and five replicates of 10 chickens each. The treatments were as follows: four diets with citric acid supplementation of 0, 12.5, 25, and 50g CA/kg. In this study, the live weight, carcass weight, thigh weight, drumstick weight, and carcass yield were higher in CA25 than in other treatments. The wing weight was higher in CA12.5 than in CA0. The highest value was determined in CA0, followed by CA12.5, and CA25, respectively, according to pH24 h, pH48 h, pH72 h, cooking loss, as well as shear force. The lowest value was recorded in CA50 as expected. The pH24 h, pH48 h, pH72 h, cooking loss, and shear force were found to be similar. The current study indicates that 12.5 and 50 g CA/kg can be used easily in the diet of male Venda chickens without any negative effects.

Keywords: indigenous chickens; meat quality; organic acid; poultry

---

 

 

Introduction

The Venda chicken breed was first observed in the Venda district of Limpopo Province (Mogesse, 2007a). It is a multicolored chicken with basic colors similar to the white, black, and brown of the region's indigenous cattle and goats (Van Marle-Koster and Nel, 2000). It has a single comb but can also have a rose comb and has five toes. Venda chickens produce few eggs but are broody and have outstanding mothering ability (Mogesse, 2007a; Mngonyama, 2012). They are fairly large in contrast to other indigenous chicken species and lay huge, colorful eggs. These chickens reach sexual maturity at 143 d, weighing an average of 2.1 kg in cocks and 1.4 kg in hens at 20 w of age (Mogesse, 2007a). The average weight of the cockerels and hens can reach up to 2.9-3.6 kg and 2.4-3.0 kg (Manyelo et al., 2020). The productivity of these chickens is generally low while mortality is high, implying that appropriate nutritional and management interventions are needed to realize their optimal production (Okitoi et al., 2006; Mbajiorgu et al., 2011).

The increase in the cost of nutritional ingredients is one of the most serious challenges for the poultry industry. The decrease in available land for food grains and feed production, climatic changes, and limited water resources influence the cost of animal feed production (Rao, 2015). To overcome this challenge, feed additives are considered essential for optimum performance and productivity in poultry production (Shahid et al., 2015). In the past, antibiotics were used to maximize the utilization of nutrients

in feed and enhance the growth performance and production of poultry (Huyghebaert et al., 2011). However, consumers are rejecting the use of antibiotics in animal feeds because of their association with human and animal health risks (Gonzalez & Angeles, 2017). Although the inclusion of alternative growth promoters (AGP) in animal feed was banned in the European Union countries in 2006, it is widely practiced in the South African poultry industry, where the effects of AGP are alleviated by feeding an AGP-free 'withdrawal' diet before slaughter. This has encouraged the exploration of alternative means to improve health, including non-therapeutic options such as enzymes, probiotics, prebiotics, herbs, essential oils, immunostimulants, and organic acids. In this regard, organic acids are selected as a promising feed additive in poultry production due to their ability to maintain gut barrier cellular integrity, modulate intestinal microbiota, improve digestion and nutrient absorption rate, and contribute to improved production performance (Dai et al., 2020). Citric acid as a tricarboxylic acid (TCA) has gained considerable attention in poultry production as it is used as an energy source for prime enterocytes (Hosna, 2018) or for the bactericidal efficacy against harmful species (for example, Escherichia coli) (Shah et al., 2018). It is volatile and corrosive in its free form; thus, CA is commercially-produced in salt forms (Huyghebaert et al., 2011) to increase palatability and bioavailability in the gut of birds (Khan & Iqbal, 2016).

Citric acid acts as a growth promoter by acidifying gastrointestinal (GI) content and is considered a favourable determinant of effective nutrient digestion (Boling et al., 2000). It also improves the performance and increases the solubility of feed ingredients and the digestion and absorption of nutrients (Nourmohammadi & Afzali, 2013). Various experiments have been conducted to quantify the effects of citric acid on poultry, but varying, and sometimes contradictory, results have been observed. Data indicate that it generally results in bodyweight and feed conversion improvements, whilst decreasing feed intake (Chowdhury et al., 2009; Haque et al., 2010; Nourmohammadi et al., 2010). Several studies have demonstrated the effect of citric acid on the physico-chemical and sensory properties of meat (Hassan et al., 2015; Kim et al., 2019). Moreover, citric acid is generally recognized as a safe antimicrobial agent, and the dilute solutions of organic acids (1%-3%) are generally without effect on the desirable sensory properties of meat (Kotula & Thelappurate, 1994). According to Langhout (2000), using an acidifier may improve the development rate and carcass quality of broiler chickens.

The current study was designed to determine whether increasing levels of citric acid in male Venda chicken diets would improve carcass characteristics and physico-chemical attributes more than those without citric acid.

 

Materials and methods

The use of animals and approval for all experimental protocols were granted by the Animal Research Ethics Committee of the University of Limpopo (Project number: AREC/10/2020: PG). The study was conducted at Animal Unit of the University of Limpopo, South Africa. Four experimental maize and soybean meal-based diets were formulated as follows: CA0 = control diet; CA12.5 = control diet supplemented with 12.5 g CA/kg feed; CA25 = control diet supplemented with 25 g CA/kg feed; CA50 = control diet supplemented with 50 g CA/kg feed (Table 1). Birds received different treatment levels of citric acid in the diet: 0, 12.5, 25,and 50 g CA/kg (Table 2). Diets were fed in three phases: formulated maize-soybean meal-based starter from day 1 to day 30, formulated maize-soybean meal-based grower from day 31 to day 60, and formulated maize-soybean meal-based finisher from day 61 to day 90.

Four dietary treatments with various CA levels were randomly assigned to 200 male, day-old Venda chicks. A completely randomized design (CRD) was used with four treatments, five replicates per treatment, and 10 chickens per replicate. The chickens were reared on bedded floor pens with 7 cm of fresh sawdust in an environmentally-controlled house for 90 d. The chickens were offered clean water and food ad íibitum. The chickens were monitored regularly, sick chickens were isolated and treated accordingly by the veterinarian. Dead chickens were taken immediately from the experimental house to the laboratory for post-mortem. Chickens received 23 h of light from 0 to 3 d of age, 20 h of light from 4 to 7 d of age, and 16 h of light from day 8 onwards.

At the age of 90 d, 20 chickens per treatment were randomly selected, separately weighed, and slaughtered by cervical dislocation method as it is one of the most prevalent methods for slaughtering individual birds and it is perceived to be humane by users, easy to learn and perform, and does not require equipment and help of veterinarian (Mason et al., 2009; Martin et al., 2016). They were allowed to completely bleed out, then de-feathered, eviscerated, weighed, and recorded. The carcass was sliced on the joints into drumsticks, wings, breast, and thighs, as well as across the shoulder area to remove the backbone from the breast. The cuts were then weighed using an electronic weighing balance (AE ADAM, United Kingdom, Milton Keynes). The live and carcass weights were recorded and the meat piece weights (drumsticks, wings, breasts, and thighs) were also recorded. The carcass yield was calculated from the ratio of the eviscerated carcass weight to the live carcass (Mendes et al., 2004).

Only breast muscles without skin were put in trays as per dietary treatment and stored at 4 °C until further analysis. The day after slaughter, two trays from each treatment were removed from the refrigerator to measure physico-chemical attributes, i.e., pH after 24 h (pH24), pH after 48 h (phUs), pH after 72 h (pH72), cooking loss, and shear force. After being chilled at 4 °C for 24 h, breast meat pectoralis major (p. major) of the left side was examined for meat pH. A digital pH meter (CRISON pH 20, Crison Instrument SA, Spain, Barcelona) was used to measure pH after calibration with pH 4.00 and 10.00 phosphate buffers.

For cooking loss determination, chilled chicken breast samples were weighed, placed into sealed polyethylene bag, and cooked on an electronic stove at 80 °C for 30 min to calculate the cooking loss. Internal chicken breast temperatures were determined using thermocouples and a data logger (Model UWTR data logger, Omega Engineering, Stamford, CT). Cooked meat samples were cooled down to ambient temperature (20 °C), dried with a paper towel (1 -ply), then reweighed. Cooking loss (%) was calculated as (Ngambu et al., 2013):

After the determination of cooking loss, cooked breast meat samples were used for shear force measurement. The shear force was measured using a Warner-Bratzler Shear machine (Tallgrass Solutions, Manhattan, Kansan) (Novakovic & Tomasevic, 2017).

Data were subjected to the analysis of variance (ANOVA) procedure of the Statistical Package for the Social Sciences (SPSS) software, version 26 (SPSS, 2019), using a one-way procedure based on the following model:

where: Y_;i = value observed for the response variable, T, in treatment, I, and its repetition, j; u = general average of all observations; T_; = treatment effect (0, 12.5, 25, and 50g C/kg); and = experimental error associated with the observation, Yy. Comparisons among means were made using Tukey's (HSD) test. The level of probability was set at P <0.05 and means ± standard deviations were reported.

 

Results and discussion

Carcass characteristics of male Venda chickens are given in Table 3. Live, carcass, breast, drumstick, and thigh weights and carcass yield were not statistically different between groups. Wing weight at 12.5 g CA/kg was higher than the other groups (P <0.05). Similarly, it was reported that supplementation of CA in the diets increased/improved the carcass features of broiler chickens (Fascina et al., 2012). The current findings are comparable to those of Aksu et al. (2007), who found a marked improvement in carcass weight and some carcass parameters such as thigh, breast, and neck with a lower CA supplementation. Chowdhury et al. (2009), Hassan et al. (2010), and Hudha et al. (2010) discovered a considerable increase in carcass yield by using CA in the feed. Islam et al. (2008) found that dietary regimens with CA supplementation did not affect carcass parameters. This discrepancy could be due to different supplemented feeds containing different percentages of nutrients.

The amount of moisture released while cooking is determined by the pH of the meat (Yusop et al., 2010). Meat products are deemed dry because meat with a high pH loses less water while cooking than meat with a low pH (Warriss, 2010). Cooking loss and shear force reflect the tenderness of the meat (Li et al., 2019). The effect of CA supplementation on physico-chemical attributes of male Venda chickens is given in Table 4. In the present study, there was a difference in the pH24, pH48, pH72, cooking loss, as well as shear force values of the meat between groups (P <0.05).

All meat samples supplemented with CA had lower pH values (pH24, pH48, and pH72) compared to the control group (P <0.05). The same trend was observed in cooking loss and shear force, which decreased as a response to increasing levels of CA supplementation (P <0.05). Honikel (2004) reported that elevated levels of CA lowered the pH of the meat resulting in less red and more yellow meat color with less shear strength (shear force) or tenderness. This researcher indicated that the pace at which pH drops will affect the color, tenderness, loss of moisture during cooking, juiciness, and the microbiological stability of a food product.

CA can also be added to drinking water. Aclkgoz et al. (2011) found that CA in drinking water did not have a beneficial effect on the productivity of male broilers. Aktas et al. (2016) reported that low pH after CA dietary supplementation had a positive effect on texture and resulted in increased waterholding capacity, moisture content, and deceased cooking losses. In a study by Islam (2012), the addition of increasing levels of CA in drinking water decreased broiler chicken pH. The low pH value of meat products is known to affect several factors such as loss of redness, shear force, and texture (Sammel & Claus, 2003). The drop in shear force of meat samples as CA content increases was attributed to a fall in pH, which affects the water binding capacity (Burke & Monahan, 2003).

 

Conclusions

According to the findings of the study, the dietary supplementation of CA, especially at 12.5 and 50 g per kg, could improve the carcass characteristics of male Venda chickens. The physico-chemical attributes could also be improved with CA supplementation by improving the pH, shear force, and decreasing cooking losses.

 

Acknowledgments

Funding was provided by the National Research Foundation (NRF); Grant number, MND210829635979.

 

Author contributions

Conceptualization, BG and JWN; validation, BG and MVM; Writing original draft preparation, MMV; Writing review and editing, BG and MVM; supervision, BG and JWN. All authors have read and agreed to the published version of the manuscript.

 

Conflict of interest declaration

The authors declare that they have no conflicts of interest relative to the content of this paper.

 

REFERENCES

Aclkgoz, Z., Bayraktar, H. and Altan, O., 2011. Effects of formic acid administration in the drinking water on performance, intestinal microflora, and carcass contamination in male broilers under high ambient temperature. Asian-Australas. J. Anim. Sci. 24(1), 96-102.         [ Links ]

Aksu, T., Ates, C. T., Erdogan, Z. & Baytok, E., 2007. The response of broilers to dietary organic acid mixture. Indian. Vet. J. 84(4), 385-387.         [ Links ]

Aktas, N., Aksu, M.I. & Kaya, M., 2016. The effect of organic acid marination on tenderness, cooking loss and bound water content of beef. J. Muscle Foods. 1,181-194.         [ Links ]

Boling, S.D., Webel, D.M., Mavromichalis, I., Parsons, C.M. & Baker, D.H., 2000. The effects of citric acid on phytate-phosphorus utilization in young chicks and pigs. J. Anim.Sci. 78, 682-689. doi: 10.2527/2000.783682x.         [ Links ]

Burke, R.M. & Monahan, F.J., 2003. The tenderization of shin beef using a citrus juice marinade. Meat Sci. 63, 161-168. https://doi.org/10.1016/S0309-1740(02)00062-1.         [ Links ]

Chowdhury, R., Islam, K.M., Khan, M.J., Karim, M., Haque, M.N., Khatun, M. & Pesti, G., 2009. Effect of citric acid, avilamycin, and their combination on the performance, tibia ash, and immune status of broilers. Poult. Sci. 88 (8), 1616-1622. https://doi.org/10.3382/ps.2009-00119.         [ Links ]

Dai, D., Qiu, K., Zhang, H., Wu, S., Han, Y., Wu, Y., Qi, G. & Wang, J., 2020. Organic acids as alternatives for antibiotic growth promoters alter the intestinal structure and microbiota and improve the growth performance in broilers. Front. Microbiol. 11, 618144.         [ Links ]

Fascina, V.B., Sartori, J.R., Gonzales, E., De Carvalho, F.B., De Souza, I.M.G.P., Polycarpo, G.D.V. Stradiotti, A.C. & Pelícia, V.C., 2012. Phytogenic additives and organic acids in broiler chicken diets. Rev. Brasi. Zootec, 41, 2189-2197.         [ Links ]

Gonzalez, R.M. & Angeles, H.J.C., 2017. Antibiotic and synthetic growth promoters in animal diets: Review of impact and analytical methods. Food Control. 72, 255-267.         [ Links ]

Haque, M.N., Islam, K.M., Akbar, M., Chowdhury, R., Khatun, M., Karim, M. & Kemppainen, B., 2010. Effect of dietary citric acid, flavomycin and their combination on the performance, tibia ash and immune status of broiler. Can. J. Anim. Sci. 90 (1), 57-63.         [ Links ]

Hassan, H.M.A., Mohamed, M.A., Youssef, A.W. & Hassan, E.R., 2010. Effect of using organic acids to substitute antibiotic growth promoters on performance and intestinal microflora of broilers. Asian-Australas. J. Anim. Sci. 10(23), 1348-1353.         [ Links ]

Hassan, R., El-Kadi, S. & Sand, M., 2015. Effect of some organic acid on some fungal growth and their toxins production. Int J Adv Biol. 2, 1-10.         [ Links ]

Honikel, K.O., 2014. Chemical and physical characteristics of meat/pH measurement. Meat Sci. 262-266. DOI: https://doi.org/10.1016/b0-12-464970-x/00117-3.         [ Links ]

Hosna, H., 2018. Application of organic acids in poultry nutrition. Int. J. Avian Wildl. Biol. 3, 324-329. DOI: 10.15406/ijawb.2018.03.00114.         [ Links ]

Hudha, M.N., Ali, M.S., Azad, M.A.A., Hossain, M.M., Tanjim, M., Bormon, S.C., Rahman, M.S., Rahman, M.M. & Paul, A.K., 2010. Effect of acetic acid on growth and meat yield in broilers. Int. J. BioL. Res. 1, 31-35.         [ Links ]

Huyghebaert, G., Ducatelle, R. & Immerseel, F.V., 2011. An update on alternatives to antimicrobial growth promoters for broilers. Vet. J. 187, 182-188.         [ Links ]

Islam, K. M. S., 2012. Use of citric acid in broiler diets. World's Poult Sci J. 68, 104-118. DOI: 10.1017/S0043933912000116.         [ Links ]

Islam, M.Z., Khandaker, Z.H. & Chowdhury, S.D., 2008. Effect of citric acid and acetic acid on the performance of broilers. J. Bangladesh Agric. Univ. 6(2), 315-320. DOI: http://dx.doi.org/10.22004/ag.econ.208308.         [ Links ]

Khan, S.H. & Iqbal, J., 2016 Recent advances in the role of organic acids in poultry nutrition. J. Appl. Anim. Res. 44, 359-369. https://doi.org/10.1080/09712119.2015.1079527.         [ Links ]

Kim, T.K., Hwang, K.E., Lee, M.A., Paik, H.D. & Choi, Y.S., 2019. Quality characteristics of pork loin cured with green nitrite source and some organic acid. Meat Sci. 152, 141 -145. https://doi.org/10.1016/j.meatsci.2019.02.015.         [ Links ]

Kotula, K.L. & Thelappurate, R., 1994. Microbiolical and sensory attributes of retail cuts of beef treated with acetic and lactic acid solutions. J. Food. Prot. 57, 665-670.         [ Links ]

Lang hout, P., 2000. New additives for broiler chickens. World's Poul. 16(3): 22-27.         [ Links ]

Li, J., Yang, C., Peng, H., Yin, H., Wang, Y., Hu, Y., Yu, C., Jiang, X., Du, H., Li, Q. and Liu, Y., 2019. Effects of slaughter age on muscle characteristics and meat quality traits of Da-Heng meat type birds. J. Anim. 10(1), 69. doi:10.3390/ani10010069.         [ Links ]

Manyelo, T.G., Selaledi, L., Hassan, Z.M. & Mabelebele, M., 2020. Local chicken breed of Africa: Their description, uses and conservation methods. J. Anim. 10(12), 2257. doi:10.3390/ani10122257.         [ Links ]

Martin, J.E., McKeegan, D.E.F., Sparrey, J. & Sandilands, V., 2016. Comparison of novel mechanical cervical dislocation and a modified captive bolt for on farm killing of poultry on behavioural reflex responses and anatomical pathology. Anim Welf. 25576(2), 227-241. DOI: https://doi.org/10.7120/09627286.25.2.227.         [ Links ]

Mason, C., Spence, J., Bilbe, L., Hughes, T. & Kirkwood, J., 2009. Methods for dispatching backyard poultry. Vet. Rec. 164(7), 220.         [ Links ]

Mbajiorgu, C.A., Ng'ambi, J.W. & Norris, D., 2011. Effect of varying dietary energy to protein ratio level on growth and productivity of indigenous Venda chickens. Asian J. Anim. Vet. Adv. 6, 344-352. DOI: 10.3923/ajava.2011.344.352.         [ Links ]

Mendes, A., Moreira, J., Oliveira, E.G., Garcia, E.A. & Almeida, M.I.M., 2004. Efeitos da energia da dieta sbre desempenho, rendimento de caracca e gordura abdominal de Frangos de corte. 33(6), 2300-2307. Rev. Bras. De Zootec. https://doi.org/10.1590/S151635982004000900016.         [ Links ]

Mngonyama, M.B.A., 2012. Morphometric characteristics and consumer acceptability of meat from Potchefstroom Koekoek, Black Australorp, Venda and Ovambo chickens. PhD thesis, University of KwaZulu-Natal, South Africa.         [ Links ]

Mogesse, H.H., 2007a. Phenotypic and genetic characterization of indigenous chicken populations in Northwest Ethiopia. PhD thesis, University of the Free State, South Africa.         [ Links ]

Ngambu, S., Muchenje, V. & Marume, U., 2013. Effect of Acacia karroo supplementation on growth, ultimate pH, colour and cooking losses of meat from indigenous Xhosa lop-eared goats. Asian-Australas. J. Anim. Sci. 26, 28-13. doi: 10.5713/ajas.2012.12046.         [ Links ]

Nourmohammadi, R. & Afzali, N., 2013. Effect of citric acid and microbial phytase on small intestinal morphology in broiler chicken. Ital. J. Anim. Sci. 12, 44-47. https://doi.org/10.4081/ijas.2013.e7.         [ Links ]

Nourmohammadi, R., Hosseini, S.M. & Farhangfar, H., 2010. Influence of citric acid and microbial phytase on growth performance and carcass characteristics of broiler chickens. Am. J. Anim. Vet. Sci. 5, 282-288.         [ Links ]

Novakovic, S. & Tomasevic, I., 2017. A comparison between Warner-Bratzler shear force measurement and texture profile analysis of meat and meat products: a review. IOP Conference Series: Environ. Earth Sci. 85, 1-7. doi:10.1088/1755-1315/85/1/012063        [ Links ]

Okitoi, L.O., Udo, H.M.J., Mukisira, E.A., de Jong, R. & Kwakkel, R.P., 2006. Evaluation of low - Input interventions for improved productivity of indigenous chickens in Western Kenya. Agric. Trop. Sub-trop. 39, 178-181.         [ Links ]

Rao, R.S.,2015. Trends and challenges of poultry industry. Int. J. Eng. Tech. Mgmt. Res. 1, 8-13. DOI: https://doi.org/10.29121/ijetmr.v1.i1.2015.21.         [ Links ]

Sammel, L.M. & Claus, J.R., 2003. Citric acid and sodium citrate effects on reducing pink colour defect of cooked intact turkey breast and ground turkey rolls. J. Food Sci. 68: 874-878. https://doi.org/10.1111/j.1365-2621.2003.tb08259.x.         [ Links ]

Shah, S.Z.H., Afzal, M. & Fatima, M., 2018. Prospects of using citric acid as poultry feed supplements. J. Anim. Plant. Sci. 28, 12.         [ Links ]

Shahid, S., Chand, N., Khan, R.U., Suhail, S.M. & Khan, N.A., 2015. Alternations in cholesterol and fatty acids composition in egg yolk of Rhode Island Red x Fyoumi Hens fed with hemp seeds (Cannabis sativa L.). J. Chem. https://doi.org/10.1155/2015/362936.         [ Links ]

Van Marle-Koster, E. & Nel, L.H., 2000. Genetic characterization of native southern African chicken populations: Evaluation and selection of polymorphic microsatellite markers. S. Afr. J. Anim. Sci. (1), 1-6.         [ Links ]

Warriss, P.D., 2010. Meat Science: An introductory text (2^nd ed.). CABI Publishing. Wallingford, England.         [ Links ]

Yusop, S.M., O'Sullivan, M.G., Kerry, J.F. & Kerry, J.P., 2010. Effect of marinating time and low pH on marinade performance and sensory acceptability of poultry meat. Meat Sci. 85(4), 657-663. https://doi.org/10.1016/j.meatsci.2010.03.020.         [ Links ]

 

 

Submitted 27 July 2023
Accepted 27 February 2024
Published 26 March 2024

 

 

* Correspondence: busisiwe.gunya@ul.ac.za