52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Physicochemical characteristics and concentration chain fatty acids short of the feces of equidae fed with
different types of forages
Madalena Lima Menezes¹, Camilla Garcia Moreira¹, Thaís Pagotti Mota¹, Graziani Ferrer Corrêa², Gabriela
Ribeiro², Camila Giunco³, Roberta Ariboni Brandi4
¹Pos Graduate program in Animal Science – FZEA/USP, Av. Duque de Caxias Norte, 225, Pirassununga/SP, Brasil. E-mail: [email protected];
[email protected]; [email protected];
²Undergraduate student in Animal Science – FZEA/USP, Av. Duque de Caxias Norte, 225, Pirassununga/SP, Brasil. E-mail:
[email protected]; [email protected];
³Undergraduate student in Veterinary Sciences – FZEA/USP, Av. Duque de Caxias Norte, 225, Pirassununga/SP, Brasil, E-mail:
[email protected];
4
Faculty member at the Department of Animal Science – FZEA/USP, Av. Duque de Caxias Norte, 225, Pirassununga/SP, Brasil,
[email protected].
Abstract: The objective of this study was to evaluate the influence of different forages on the concentration of
short-chain fatty acids (SCFA) and the chemical characteristics of the feces. The analyzed conducted were as
follows: pH, buffer capacity (BC) and production of short chain fatty acids in the feces. Six animals were used
(three horses and three mules), with approximately 14 months and 318.93 ± 35.35kg, housed in individual pens.
Three treatments were provided ad libitum with the proportions: 100% of Coast-Cross hay, 56% of Coast-Cross hay
and 44% of chopped Elephant grass; and 100% of chopped Elephant grass. The design was completely randomized
in a 2x3 factorial. There was a significant effect of the forages type on the pH and BC of the feces, as well as on the
concentration of acetic acid, butyric acid and total SCFA. It was observed higher pH values for the hay and chopped
grass, compared with the mixture of them, same behavior presented by the buffering capacity and the production of
larger concentrations of acetate, butyrate and total SCFA in feces. There was no effect on concentrations of
propionic, isobutyric, isovaleric and valeric acids. There was no effect of the species on the concentrations of the
total SCFA and its fractions. Hay-based diets provide the generation of higher concentrations of acetate in the feces
and allows the maintenance of pH and CT values.
Keywords: fatty acids, horses, mules, pH
Características fisico-quimicas e concentração de ácidos graxos de cadeia curta nas fezes de equideos
alimentados com diferentes tipos de volumosos
Resumo: O objetivo do presente estudo foi avaliar a influência dos diferentes volumosos sobre a concentração de
ácidos graxos de cadeia curta (AGCC) e as características químicas das fezes. Foram avaliados: pH, capacidade
tamponante (CT) e produção de ácidos graxos de cadeia curta nas fezes. Foram utilizados seis animais (três equinos
e três muares), com aproximadamente 14 meses e 318,93 ± 35,35kg, alojados em baias individuais. Foram
fornecidos três tratamentos ad libitum com as proporções: 100% de feno de Coast-Cross;56% de feno de CoastCross e 44% de capim Elefante picado; e 100% de capim Elefante picado. O delineamento foi inteiramente
casualizado em esquema fatorial 2x3. Houve efeito (P<0,05) do tipo de volumoso sobre o pH e CT das fezes, bem
como sobre a concentração de ácidos acético, butírico e AGCC totais. Foram observados maiores valores de pH
para o feno e o capim picado, quando comparado com a mistura dos dois, mesmo comportamento apresentado pela
capacidade tamponante e a produção de maiores concentrações de acetato, butirato e AGCC totais nas fezes. Não
foi observado efeito sobre as concentrações dos ácidos propiônico, isobutírico, isovalérico e valérico. Não houve
efeito da espécie sobre as concentrações dos AGCC total e suas frações. Dietas a base de feno proporcionam a
geração de maiores concentrações de acetato nas fezes bem como permite a manutenção dos valores de pH e CT.
Palavras–chave: ácidos graxos, cavalos, muares, pH
Introduction
Horses are herbivore animals able to meet most or all of their nutritional demand by eating grasses. The
structural carbohydrates are energy sources for horses, due to the production of short chain fatty acids (SCFA) by
intestinal fermentation (NRC, 2007).
Food intake has the ability to change the fermentation type that occurs in the large intestine, making it
necessary to measure from physico-chemical characteristics of the feces (pH, buffering capacity, and concentration
of SCFA) (Godoi et al., 2009) . Changing these parameters can affect the action of cellulolytic bacteria, decreasing
the production of acetic acid (Chalupa et al., 1986) which is the major fatty acid produced in diets composed mainly
bulky (Moore-Colyer et al., 2000).
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
The forage supply is important for the normal functioning of the digestive tract and prevention of behavioral
disorders resulting from reduced levels of fiber in the diet, indicating the importance of quality of bulky, due to the
greater availability of energy (Moore-Colyer et al ., 2000). Mules exhibit greater efficiency in the digestion of lowquality fibers being one of the main differences between species (NRC, 2007).
Zeyner et al. (2004) observed that the increase in hay intake of 0.5 to 1.0 kg/100 kg of body weight/day,
increased the concentration of acetate and a decrease in the concentration of SCFA and the molar concentration of
propionate.
The objective of this study was to evaluate the influence of different forages on the concentration of shortchain fatty acids and the chemical characteristics of the stool.
Material and Methods
The experiment was conducted in Sector Equideocultura, FZEA/USP, campus Pirassununga, using six
animals (three horses and three mules), aged approximately 14 months and live weight of 318.93 ± 35.35kg, housed
in individual pens. Three treatments ad libitum were provided with the following proportions: 100% of Coast-Cross
hay (Cynodon dactylon (L.) Pers); 56% of Coast-Cross hay and 44% of chopped Elephant grass (Pennisetum
purpureum); and 100% of chopped Elephant grass.
For the determination of pH and buffering capacity, samples of the first feces of the day were collected and
packed in plastic bags. The pH was measured by pH meter. The BC was performed according to the method
described by Zeyner et al. (2004).
For determination of short chain fatty acids (SCFA) were collected approximately 100g of the first feces of
the day of each animal, which were filtered with ruminal fluid filter cloth and placed in 50 mL falcon tubes. The
samples were centrifuged and the supernatant was pipetted into 2 mL eppendorfs® and analyzed by gas
chromatography.
The experimental protocol consisted of three periods, with duration of seven days each (five days of diet
adaptation and two days of sampling for evaluating the characteristics of feces). The statistical design was
completely randomized, arranged in a factorial 2 (two species) x 3 (three forms of bulky presentation) and the
results were analyzed using the computer program Statistical Analysis System (SAS, 2004), using the MIXED
procedure.
Results and Discussion
Effect was observed (P<0.05) of different forages on the fecal pH and buffering capacity (BC5 and BC6)
(Table 1).
Table 1. Effect of different forages on the pH and buffer capacity (BC5 ad BC6) on
the feces.
Treatments
Variables
CV (%)
P
Hay +
Hay
Chopped grass
Chopped grass
pH
7.29±0.06ª
6.98±0.06b
7.32±0.06ª
4.38
0.0112
BC5
18.33±0.32ª
13.77±0.32b
18.96±0,32ª
27.26
0.0106
BC6
6.72±0.20b
5.19±0.20c
8.85±0.20ª
33.11
0.0005
Means, in line, followed by different letters are different by t test (P<0.05).
There was an effect (P<0.05) of different forages types on the acids: acetic, butyric and total concentration of
SCFA, but there was no effect (P>0.05) on the concentrations of acids: propionic, isobutyric, isovaleric and valeric
(Table 2).
Table 2. Effect of different forages concentrations of acids: acetic, propionic, isobutyric,
butyric, isovaleric, valeric and total SCFA.
Treatments
Variables
CV (%)
P
Hay +
Hay
Chopped grass
Chopped grass
Acetic (mmol/L)
16.37±1.46ª
15.22±1.46ª
8.86±1.46b
35.76
0.0051
Propionic (mmol/L)
4.62±0.31ª
4.57±0.31ª
3.89±0.31ª
21.48
0.2314
Isobutyric (mmol/L)
0.43±0.05ª
0.37±0.05ª
0.37±0.05ª
31.56
0.3637
Butyric (mmol/L)
1.11±0.15ª
0.91±0.15ab
0.51±0.15b
51.52
0.0370
Isovaleric (mmol/L)
0.29±0.05ª
0.24±0.05ab
0.17±0.05b
52.71
0.1053
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Valeric (mmol/L)
Total SCFA (mmol/L)
0.08±0.03ª
22.92±1.95ª
0.05±0.03ab
21.35±1.95ª
0±0.03b
13.80±1.95b
167.99
32.04
0.1094
0.0110
Means, in line, followed by different letters are different by t test (P<0.05).
There wasn’t a species effect (P>0.05) on the concentrations of acids: acetic, butyric, propionic, isobutyric,
isovaleric, valeric, and total SCFA (Table 3).
Table 3. Effect of the species on concentrations of acids: acetic, propionic,
isobutyric, butyric, isovaleric, valeric, and total SCFA.
Species
Variables
CV (%)
P
Equine
Mule
Acetic (mmol/L)
12.78±1.50ª 14.19±1.50ª
35.76
0.5236
Propionic (mmol/L)
3.87±0.25b
4.84±0.25ª
21.48
0.5388
Isobutyric (mmol/L)
0.36±0.06ª
0.42±0.06ª
31.56
0.5388
Butyric (mmol/L)
0.83±0.15ª
0.86±0.15ª
51.52
0.9144
Isovaleric (mmol/L)
0.22±0.06ª
0.24±0.06ª
52.71
0.8156
Valeric (mmol/L)
0.02±0.03ª
0.07±0.03ª
167.99 0.2980
Total SCFA (mmol/L) 18.09±1.95ª 20.63±1.95ª
32.04
0.3845
Means, in line, followed by different letters are different by t test (P<0.05).
For the pH, it was observed that there was a significant effect of different forages, but the average of the
values obtained in this study (7.20), is above the values recommended by Pagan (2001), which mentions that the
fecal pH should range 6.5 to 7, indicating that the fiber fermenting bacteria present a better performance close to
this variation. The values obtained are also at odds with Zeyner et al. (2004), working with horses fed hay and
concentrate values found pH 6.4 to 6.7, possibly due to the inclusion of concentrate in the diet.. The literature is
sparse with respect to pH values for mules, making it difficult to compare this literary data with this specie.
The mean values found for BC5 and BC6 were 17.02 mL and 6.82 mL respectively for the treatments. The
type of dietary fiber may influence the pH and BC because, according to NRC (2007), the structural carbohydrate
of forages are important buffering sources and thus help to maintain conditions suitable for fermentation in the large
intestine.
There was greater concentration of acetate in all treatments, agreeing with the findings of Zeyner et al.
(2004) mentioning that in diets forage base the main fatty acid is produced acetate, although it occurs the
production of propionate and butyrate in smaller proportions.
Moore-Colyer et al. (2000) mentioned that the diet quality influences the production of short chain fatty
acids, and that diets with predominantly forage, acetate has higher concentrations in the feces, the same situation
observed in this study (Table 1).
There was no difference (P>0.05) for species effect, but observed that mules have a greater production of
SCFA regardless of the diet used, corroborating NRC (2007) mentioned that animals of this species have higher
digestive efficiency in low quality forages.
Conclusions
Hay-based diets provide generation of higher concentrations of acetate in the feces and allows the
maintenance of pH and BC values.
References
Chalupa, W.; Vecchiarelli, B.; Elser, A. E.; Kronfeld, D. S.; Sklan, D.; Palmquist, D. L. Ruminal fermentation in vivo as
influenced by long-chain fatty acids.1986. Journal of Dairy Science, n.5, 69:1293-1301.
Godoi, F. N.; Almeida, F. Q.; Guarienti, G. A.; Santiago, J. M. Junior, D. G; Nogueira, Y. C.; Brasileiro, L. S. 2009. Perfil
hematológico e características das fezes de equinos consumindo dietas hiperlipidêmicas. Revista Ciência Rural, Santa Maria,
v.39, n.9, p. 2571-2577.
Moore-Colyer, M. J. S.; Hyslop, J. J.; Longland, A. C.; Cuddeford, D. 2000. Intra-caecal fermentation parameters in ponies fed
botanically diverse fibre-based diets. Animal Feed Science and Technology. 84:183-197.
National Research Council – NRC. 2007. Nutrient Requirements of Horses. 6th edition. Washington, D.C.: National Academy
Press. 341p.
SAS Institute, Inc.SAS/STAT User´s guide.12th Edition. 2004.SAS Inst. Inc., Cary, NC.
Zeyner, A., Geibler, C., Dittrich, A. 2004. Effects of hay intake and feeding sequence on variables in faeces and fecal water (dry
matter, pH value, organic acids, ammonia, buffering capacity of horses). Journal Animal Physiology and Animal Nutrition,
88:7-19.
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