Revista Agrária Acadêmica
doi: 10.32406/v8n2/2025/132-140/agrariacad
Natural chicken carcass-based food for competition dogs. Alimentação natural a base de carcaça de frango para cães atletas.
Dinnara Layza Souza da Silva
1*, Mérik Rocha-Silva1, Samira Teixeira Leal de Oliveira1, Maurílio Souza dos Santos Couto1, Francisco Marques Cardozo Júnior1, Débora Araújo de Carvalho1, Kíria Bianca Sousa de Morais2
1- Docente do Curso de Zootecnia – Centro de Ciências Agrárias – Universidade Estadual do Piauí – UESPI, Teresina/PI.
2- Discente do Curso de Zootecnia – Centro de Ciências Agrárias – Universidade Estadual do Piauí – UESPI, Teresina/PI.
* Autor para correspondência. E-mail: dinnara.layza@cca.uespi.br
Resumo
Avaliações nutricionais de palatabilidade e aceitabilidade de dietas, são importantes para orientações nutricionais de cães atletas. Assim, objetivou-se determinar a preferência alimentar de cães atletas. O experimento foi conduzido em canil, onde testou-se a preferência de duas dietas, a dieta RC (ração premium) e a dieta AN (carcaça de frango). Foram acompanhados 12 cães adultos, machos e fêmeas, da raça Pastor Alemão, pesando entre 20 e 25 kg, alimentados duas vezes ao dia (09:00 e 17:00 horas), para atender às necessidades de energia metabolizável (NEM). No teste de preferência alimentar, utilizou-se duas vasilhas com as dietas ofertadas ao mesmo tempo, com controle de ofertado e sobras. A análise dos dados de preferência alimentar e consumo (g/dia) se deu por meio dos testes de Quí-Quadrado de Fischer, teste F e Tukey, todos à 95% de probabilidade (𝛼:0,05) via software R. Não houve diferença significativa entre a preferência por AN ou RC (p-valor > 0,05) pelo teste QQ. Consumo total de 9,1 Kg de AN e 7,7 de RC, submetidos aos testes de média identificou-se, ajuste à distribuição Gaussena (AIC 520), conforme análise de variância, observou-se diferença significativa no consumo (p-valor ≤ 0,05), em a média de consumo de RC foi de 374 g e de AN foi de 319 g. A taxa de ingestão para AN foi de 57,78 % e 42,27% para RC. Não houve diferença significativa para o tempo de alimentação. No aspecto fisiológico, os cães alimentados com RC apresentaram maior volume de fezes, de aspecto endurecido, pouco odor e sem muco. Não houve registro de alterações comportamentais nos cães. Conclui-se que a AN pode ser igualmente utilizada na nutrição, equivalente a RC, como opção viável para compor dieta de cães, sem prejuízo à performance durante preparo para competições.
Palavras-chave: Alimentação natural. Mercado pet. Pet food. Zootecnia.
Abstract
Nutritional palatability and acceptability assays of diets are important to guide the nutrition of competition dogs. From this perspective, this study aimed to determine the food preference of competition dogs. The experiment was conducted in a kennel by testing the preference of two diets: TC diet (premium dog food) and AN diet (chicken carcass). Twelve adult dogs, among males and females, of the German Shepherd breed and weighing from 20 to 25 kg were fed twice a day (9:00 a.m. and 5:00 p.m.), to meet their metabolizable energy requirements (NEM). In the food preference assay, two containers were used by offering the two diets at the same time, with the control of food supplied and leftovers. The analysis of food preference and consumption (g/day) occurred though Fischer’s chi-square, F, and Tukey tests all at 95% probability (𝛼:0.05) via software R. There was no significant difference between the preference for AN or RC (p-value > 0.05) by the QQ test. The total consumption of 9.1 Kg of AN and 7.7 of RC, subjected to the test of means, adjusted to a Gaussian distribution (AIC 520). According to the analysis of variance, there was a significant difference in consumption (p-value ≤ 0.05), with the average consumption of RC amounting to 374 g, whereas for AN it was 319 g. The intake rate for AN was 57.78 %, and 42.27% for RC. There was no significant difference for the feeding time. With regard to the physiological aspect, the dogs fed with TC showed a higher volume of feces, which had a hardened aspect, little odor, and no mucus. There was no record of behavioral changes in the dogs. I tis concluded that AN can be equally used for dog nutrition, similar to RC, as a viable option to compose the diet of dogs without compromising their performance during preparation for competition.
Keywords: Natural diet. Pet market. Pet food. Zootechnics.
Introduction
The Brazilian Association for the Industry of Companion Animal Products (ABINPET) has exposed, in its latest report, the increasingly effective participation of the pet market in the Brazilian agribusiness, especially after the COVID-19 pandemic, with Brazil standing out in the worldwide revenue ranking within the pet segment, second only to the United States, responsible for 43.7% of the market, and China, with 8.7% (ABINPET, 2023).
Several market segments have grown within the pet product industry (e.g., pet food and pet vet), amounting to 10.6% of the 2023 revenue, with total values estimated at R$ 46.42 billion, especially for the pet food segments, representing 78% of this revenue (ABINPET, 2023).
The importance of the pet food market is based on the perspective of providing better quality of life to pets through healthy diets, thus reducing the incidence of diseases and increasing their active life expectancy (BONTEMPO, 2005).
Along with the growing concern with animal health, there has been an increase in the demand for diets based on natural foods, giving rise to specialized products aimed at meeting the nutrient requirements of each animal according to breed, activity level, and age, thus establishing new pet food niches, e.g., the introduction of functional foods to diets, which modify the gastrointestinal physiology, promote changes in biochemical parameters, improve brain functions, and can reduce or minimize the risk of developing specific pathologies (CERBO et al., 2017).
This trend is based on the growing humanization of dogs, whose profiles are shaped after their tutors. In this scenario, being highly adaptable, the natural diet can be also classified as therapeutical, i.e., diets formulated for each specific case and meeting the nutrient demands of different health conditions (JERICÓ et al., 2017).
Natural diets employ fresh and organic foods, either cooked of raw, grain-free, and protein-focused, which are enriching ingredients. Among the possible options, the BARF diet (Biologically Appropriate Raw Foods) can be included into dietary programs of dogs as their digestive system is prepared to digest raw meat. Thus, this type of died can meet the nutritional requirements of canids if quality protein and fat sources are used (FREEMAN et al., 2013).
However, given the diversity of available natural diets, it is necessary to perform experimental assays on food preference associated with palatability tests to determine factors that affect the feeding rate and food consumption. Food preference and palatability are intimately related, and both determine, for example, which food sources will be sought by animals (ZANATTA et al., 2017).
There has been an evident increase in the capital invested on animal care, with a demand by part of the industry and the market for information about food planning for dogs. In this scenario, it is necessary to conduct research to identify the preference of animals as well as the physiological effects resulting from the modification of diets. From this perspective, this study proposed to determine the food preference of German Shepherd dogs by evaluating their acceptance of a diet based on chicken carcass compared to commercial dog food.
Material and methods
The experiment was conducted at the Terra Cajuína Kennel (Canil Terra Cajuína), located in Teresina/PI, at the following coordinates: 05º 05’ 21” S, 42º 48’ 07” W, at an elevation of 72 m above sea level.
The Terra Cajuína Kennel is specialized in the raising of German Shepherds, sale of juveniles, and exhibition and competition of this breed. The project was approved by the Ethics Committee on the Use of Animals in Research (CEUA) under protocol number 006266/2021-76.
The animals underwent an adaptation process to the diet proposed in the experiment before the evaluations were carried out. In total, 12 adult dogs were monitored, consisting of males and females weighing from 20 to 25 kg, fed twice a day (from 9:00 a.m. to 5:00 p.m.). Water was provided ad libitum.
Two diets were evaluated: a control diet (RC – commercial dog food) and an alternative diet (AN – natural food composed of chicken carcass), in two days of experiment. Food preference and first choice assays between the foods offered were carried out according to the treatments: RC (commercial food) versus AN (natural food), as seen in Figure 1.
Figure 1 – Distribution of the containers with the experimental diets: (A) natural food and (B) commercial food.
In the food preference test, two containers were used with the experimental diets (AN and RC) at the same time, and the amount initially provided as well as the leftovers being weighed to determine the food intake rate (%) and mean consumption (g/animal/day), which were compared for 30 minutes.
The palatability and food preference assays followed the methodology of Hall et al. (2018), and the food intake rate was calculated according to the following equation:
Food intake rate (%) = [ g ingested in diet A or B/ total g provided (A+B)] x 100
The first choice of each individual was recorded by taking note of which container was chosen when both foods were offered simultaneously, based on the dual-choice method (SOLÀ-ORIOL et al., 2009), with the response variable corresponding to which of the two containers the animal preferred. The positions of the containers were changed on the following day to prevent position-related preferences.
Experimental design
The design adopted in this assay was completely randomized, with 12 experimental units (animals) and four feeding sources (replications). The statistical analysis consisted of previous verification of data consistency and verification of compliance with assumptions for the least squares method.
Fisher’s chi-square test was performed with two contingency tables, both constructed by meeting the assumptions. The data were clustered both regardless of sex and per sex (M and F), in all cases considering an α of 0.05.
The data on the total daily intake per animal were subjected to verification of assumptions using the least squares method through the Shapiro-Wilk test at a 95% confidence level using the resources of the statistical package RVAideMemoire (HERVÉ; HERVÉ, 2020).
Generalized Linear Models were employed to circumvent the issue associated with data normality by testing the main distribution families arranged using the R Software GML command for variance analysis, and post hoc analysis via Tukey test, defined as a function of the coefficient of variation (CV) of the response variables consumption and time spent per meal.
Results and discussion
The animals sought the diet containing chicken carcass significantly more. For this dietary option (AN), nearly all the food made available was consumed (335 g), except for one female (Atenas), which consumed only 200 g. That could be an intrinsic behavior of the animal since that individual also did not consume all the commercial dog food (RC) when she chose it. The consumption of this animal was depicted in the hollow circles of Figure 2.
Figure 2 – Boxplot of consumption (g) per meal referring to the different diets.
Overall, 16.3 kg of food was consumed, i.e., each animal consumed, on average, 681 g per day. Of these, 9.1 kg corresponded to natural food (AN) and 7.7 kg corresponded to commercial dog food (RC). Fisher’s chi-square test indicates that the differences in consumption were not statistically significant, not even when the contingency table clustered the preferences per sex (Table 1).
Table 1 – Chi-square test of independence between preferences and experimental diets. AN: natural food; RC: commercial dog food; QQ-F: Fisher’s chi-square test with an α of 0.05.
Diet |
Observed |
Expected |
p-value QQ-F |
||
AN |
29 |
24 |
0.149 |
||
RC |
19 |
24 |
|||
F |
M |
F |
M |
||
AN |
26 |
3 |
24.16 |
4.83 |
0.236 |
RC |
14 |
5 |
15.83 |
3.16 |
|
Figure 3 exposes the frequency of choice of the animals through the calculation of the food intake rate (%), showing that the animals consumed all the food supplied with a high frequency, indicating the qualification of the food options used to compose animal diets.
Figure 3 – Food intake rate of dogs as a function of sex. Orange bar (food intake for commercial dog food); Blue bar (food intake for natural food).
The natural food the dogs were fed was composed of chicken carcass, whereas the same premium commercial dog food was provided for all dogs. The animals preferred natural food as no leftovers were observed, unlike the commercial food, for which some leftovers remained in the containers.
On the first day of experiment, 9 (nine) out of 12 (twelve) animals chose natural food (75%) whereas only 3 (25%) chose the commercial food. In the second meal of the day, 7 (58.3%) of the 12 animals chose natural food, and the remaining 5 (41.7%) chose the commercial food.
In the first meal of the second day of experiment, 7 (seven) out of 12 (twelve) animals chose natural food, and the remaining 5 chose commercial food. In the second meal of the day, 6 out of 12 animals chose natural food, whereas 6 opted for commercial food.
Without significant variation, the heteroscedasticity is evident in data distribution, whose residuals did not present a normal distribution by the Shapiro-Wilk test, thus inducing analysis using generalized linear models (GLM).
The GML were evaluated with all distribution families predicted by the function with the same name in the native package (Stats), with 4 showing convergence, indicating no significant effect of the diets on feeding but rather on consumption (grams/animal/feeding), with the Gaussian distribution showing the best adjustment to data distribution, as seen in Table 2.
Table 2 – Significance of the analyses of variance according to generalized linear models in four distributions.
Variable |
Distribution |
p-value |
AIC |
Consumption |
Gaussian |
<0.001 |
519.99 |
Consumption |
Gamma |
<0.001 |
535.01 |
Consumption |
Inverse gaussian |
<0.001 |
545.28 |
Consumption |
Poisson |
<0.001 |
801.31 |
Time |
Gaussian |
0.19 |
125.58 |
Time |
Gamma |
0.188 |
135.34 |
Time |
Inverse gaussian |
0.188 |
146.38 |
Time |
Poisson |
0.534 |
162.28 |
The commercial food (RC) showed a lower number of meals (19) compared to AN. However, the intake was statistically higher for RC (p-value < 0.05).
The weighted averages subjected to the t-test via GLM under the Gaussian distribution indicate a significant intake difference per meal, with the consumption of 318.79 g of AN and 373.68 g of RC, as indicated in Figure 4.
Figure 4 – Feeding behavior of dogs according to different experimental diets (AN: natural food; RC: commercial dog food).
With regard to the time spent eating, there was no significant difference in relation to the type of diet.
The dog feeding dynamics in the kennel takes place through two daily meals: one at 9:00 a.m. and another at 5:00 p.m., with the animals drinking water ad libitum during the day. As seen in Figure 4, the mean time spent feeding did not vary statistically between the two diets provided.
The total feeding time was 6.5 minutes on the first day and 6.9 minutes on the second day of experiment, with 3.24 minutes for diet AN and 3.58 minutes for RC.
According to Hall et al. (2018), palatability is defined as the momentary and subjective orosensory pleasantness of consumption. Thus, it is suggested that food preference and first choice analyses should be carried out to infer about palatability.
During the days of experiment, the dogs left leftovers of, on average, 353.5 grams of commercial food (RC), but there were no leftovers when natural food was provided. The average amount in grams of each of the two diets provided for each animal was 400 g of commercial food and 335 g of natural food, according to the calculations of the metabolizable energy requirement by age, size and breed of animals.
Along with food preference, the first-choice test is a parameter used to estimate palatability, i.e., the set of physicochemical features of food, e.g., flavor, texture, and odor, which cause a pleasant physiological sensation, with the food being recognized as tasteful and pleasant to be consumed (RIVERA et al., 2019; ZANATTA et al., 2017).
It should be noted that dogs have a neophilia behavior, i.e., they like to try foods with different flavors and textures. As a result, it is important to familiarize these animals while still juveniles to different types of food, textures, and flavors (KOH et al., 2020).
During the experiment, the animals were physiologically monitored in terms of score, volume, and odor of their feces, thus revealing that the animals that chose the commercial food produced a higher volume of feces, which were hardened, with less odor, and without mucus, in relation to the feces of the AN diet, probably due to the presence of fibers in the latter, which assist in the correct absorption of nutrients through the intestine by regulating the intestinal transit and also by serving to sustain the microbiota, related to intestinal health and actively participating in digestion, ensuring that nutrients are thoroughly utilized.
The food management of German Shepherds should be carried out carefully since this breed is among the most prone to develop allergies and food hypersensitivity. As a result, it is essential to combine nutrients and vitamins omega 3 and 6 in the composition of their diets. Furthermore, the genetic composition of these animals seems to be the main predisposing factor in cases of allergies (ROSSER, 1993; MORENO; TAVERA, 1999; WHITE, 2001; CHESNEY, 2002).
Therefore, the decision of testing the inclusion of chicken carcass in the diet of German Shepherd dogs was done carefully, given the predisposition of these animals to food allergies and considering that the chicken protein is one of the most common allergens among dogs, along with beef protein, milk, eggs, maize, wheat, and soybean (WHITE, 1986).
According to a study carried out by Sandri et al. (2017), there is a direct effect of the diet on the formation of feces and the intestinal microbial population. According to these authors, balanced diets resulted in a balanced intestinal microbiota and, consequently, in changes in the final products of fermentation, with a higher concentration of lactic acid in the feces of animals that received the raw diet compared to the extruded commercial diet.
After each meal, the dogs showed somnolence with both types of diet and consumed water ad libitum. Thus, the introduction of chicken carcass as a natural food in the diets of dogs preparing for competition and exhibition yielded no behavioral changes in the animals.
Conclusion
Natural food (AN) based on chicken carcass can be used equally to commercial dog food (RC) to feed German Shepherds.
The adoption of an alternative diet to commercial food brought no behavioral changes in the animals, indicating to be fully possible to adopt chicken carcass to compose the diet of sport dogs, with no damage to their performance during preparation for competition.
Conflitos de interesse
Não houve conflito de interesses dos autores.
Contribuição dos autores
Dinnara Layza Souza da Silva – orientação para o diagnóstico local e intervenção, correções e redação final; Mérik Rocha-Silva – análises dos dados e redação; Samira Teixeira Leal de Oliveira, Maurílio Souza dos Santos Couto, Francisco Marques Cardozo Júnior e Débora Araújo de Carvalho – leitura e contribuição na redação e discussão dos resultados; Kíria Bianca Sousa de Morais – execução e coleta de dados da pesquisa.
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