TECHNICAL NOTE

Effect of distillers dried grains with solubles on the morphometric of the gastrointestinal tract and internal organs of growing rabbits

Efecto de granos de destilería secos con solubles (DDGS) en la morfometría del tracto gastrointestinal (TGI) y órganos internos de conejos en crecimiento

Ysnagmy Vázquez,^I H. Bernal,^II M. Valdivié,^I E. Gutiérrez,^II L. M. Mora,^I C. A. Hernández,^II

ABSTRACT

A total of 56 growing rabbits (Black Aztec x Chinchilla) from 40 days of age were used in order to study the effect of including 0, 10, 20 and 30 % of distillers dried grains with corn solubles on the morphometric of the gastrointestinal tract ( GIT) and internal organs in a diet based on sorghum-soya. At the end of the fattening (56 days), 32 rabbits were slaughtered (eight per treatment) and the stomach full and empty, caecum and intestines were weighed, as well as the internal organs liver and spleen, all expressed as absolute weight(g), relative weight (g g^-1) and metabolic weight (g g 0.75^-1). With 30 % of distillers dried grains with corn solubles the higher weights  of the stomach full and empty, absolutes (93.75 and 33.75 g), relatives  (4.54 and 1.58 g) and metabolic (0.31 and  0.11 g g0.75^-1) were obtained. There were not differences in the relative weight and metabolic weight of the liver and spleen. It is concluded that the morphometric of the gastrointestinal tract and internal organs of rabbits is not affected with the inclusion of up to 30% of distillers dried grains with corn solubles.

Key words: distiller dried grains with corn solubles, rabbits, morphometric, alternative food.

RESUMEN

Se utilizaron 56 conejos (Negro Azteca x Chinchilla) en crecimiento a partir de los 40 días de edad para estudiar el efecto de incluir 0, 10, 20 y 30 % de granos de destilería secos con solubles de maíz en la morfometría del tracto gastrointestinal (TGI) y órganos internos en una dieta basada en sorgo-soya. Al finalizar la ceba (56 días), se sacrificaron 32 conejos (ocho por tratamiento) y se pesó el estomago lleno y vacío, ciego e intestinos, así como los órganos internos hígado y bazo, expresados todos como peso absoluto (g), relativo (g g^-1) y metabólico (g 0.75^-1).  Con 30 % de granos de destilería secos con solubles de maíz se obtuvieron los mayores pesos del estómago lleno y vacío,  absolutos (93.75 y 33.75 g),  relativos (4.54 y 1.58 g) y metabólicos (0.31 y 0.11 g g0.75^-1). El peso absoluto del hígado disminuyó (P ≤ 0.05) con la inclusión de 30 % de DDGS. Se concluye que la morfometría del tracto gastrointestinal y órganos internos de los conejos no se afecta con la inclusión de hasta 30 % de granos de destilería secos con solubles de maíz.

Palabras clave: granos de destilería secos con solubles de maíz, conejos, morfometría, alimentos alternativos.

INTRODUCTION

In recent years, the ethanol production from grains fermentation was increased worldwide, in order to reduce the oil dependence and contribute to improving the environment by means of generating biofuels. This process generates distillers to be used mainly in animal feeding (Martinez 2011), which can be an important alternative for rabbit feeding.

The distillers dried grains with corn solubles (DDGS) are used in cattle feeding (Li et al. 2011) and more recently in birds (Guney et al. 2013) and pigs (Graham et al. 2014). However, in rabbit species there are fewer references to the use of such supplement. Some works deal with the productive performance (Vazquez et al. 2013, Alagón et al. 2015) and other nutrient digestibility (Alagón et al. 2013, cited by Alagón 2013). In the reviewed literature, only Liñán (2012) and Alagón (2013) report morphometric studies in rabbits fed DDGS. Dietetic fiber in DDGS is, mainly, insoluble. This may be of interest since their inclusion in feeds may affect the morphometric of the gastrointestinal tract (GIT) and their physiology. In previous experiments performed in rabbits it was showed that the quantity and quality of the fiber are important for their effects on regulating digesta and the efficiency of nutrients use (Arruda et al. 2003).

The objective of this paper was to study the effect of the inclusion of DDGS on the morphometric of the gastrointestinal tract (GIT) and internal organs of growing rabbits.

A total of 56 rabbits of the hybrid Black Aztec x Chinchilla were used, weaned, with 40d of age and 752 g as average weight. The animals were allocated in galvanized wire cages (two animals per cage, belonging to the same litter) with dimensions of 840 x 330 mm, provided of feeder and drinker. They were distributed according to completely randomized design in four experimental groups with eight repetitions each. The inclusion levels of DDGS in the diet were 0, 10, 20 and 30%. Diets were prepared according to the requirements for rabbit in accordance with the Committee on Animal Nutrition and National Research Council (1977). The composition and contribution calculated of diets are shown in table 1.

At the end of the fattening period (96 d of age), 32 rabbits (eight per treatment) were slaughtered, with 2.2 kg as average weight. Previous to slaughter, animals were desensitized by the contusion method according to the technique described by Baumans et al. (1997).

From the gastrointestinal tract (GIT) the stomach full and empty were weighed and the caecum (without emptying) were weighed too. In addition, the small and large intestines without emptying were weighed together, so the variable intestines weight was formed. From the accessory organs, liver and spleen were individually weighed. The weights were expressed as absolute weight (g), relative (g/g) and metabolic (g^0.75).

Analysis of variance by means of the statistical program SPSS for Windows version 15.0 (Visauta 1998) was conducted. The comparison Duncan (1955) test was applied in necessary cases.

These results may be due to the higher fiber content of feed with 30% of inclusion of DDGS and, in parallel, to its lower energy concentration, which leads to the increase of food intake, as reported a previous study of Vázquez et al. (2013). Gidenne and Ruckebusch (1989) stated that when increasing the fiber increases the rate of passage through the GIT, with decrease in nutrients absorption and increase of food intake by the animals which needs to satisfy their energy needs. The increase of the stomach weight may be due to the adaptation to higher intake and, as consequence, the need to support higher weight of food (Carabaño et al. 1984).

Alagón (2013) conducted a research in which different levels of DDGS from barley, wheat or corn in growing rabbits were included. This author did not found differences in the morphometric of the digestive tract at 42 d of age of the rabbits, except in the caecum weight, which was lower in rabbits fed with 20% of inclusion of DDGS of barley, which does not coincide with that obtained in this study.

The data corresponding to the absolute, relative and metabolic weight of liver and spleen are shown table 3. The absolute liver weight decreased (P ≤ 0.05) with the inclusion of 30% of DDGS. This result not influence on the organ function and in the hepatic glycogen deposition, when not differ with respect to live weight and metabolic weight of animals which intake diets with 10 and 20%.

The results of this study show that the inclusion of DDGCS up to 30% does not cause disorder in the morphometric of the gastrointestinal tract and internal organs of rabbits, which shows that can be an alternative to be used in diets for growing rabbits. Digestibility researches are suggested to determine its effect on degradability and feed efficiency.

REFERENCES

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Received: 6/1/2015 ]]> Accepted: 23/6/2016

Ysnagmy Vázquez, Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba. Email: ysnagmy@ica.co.cu