Cabrera, R

Castillo, A

Vial, E

Villarroel, P

English

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Rumen fermentativeactivity in the goat andsheepCabrera, R.*, Villarroel, P., Vial, E., Castillo, A.Animal Digestive Physiology Laboratory,Institute of Nutrition and Food Technology, University of Chile,Casilla 15138, Santiago 11, Chile'To whom correspondence should be addressedMeasurements of rumen function were made on sheep andgoats fed the same range of diets. Differences between sheepand goats with respect to gas production rate, glucosefermentation, nitrate reduction capacity, total VFA productionand individual VFA concentration were found especially whenthe inoculum was obtained from lucerne fed animals. Theresults suggest that different pathways or groups of micro-organisms may be involved in the two species of ruminants.Metings van rumen funksie is gedoen op skape en bokke watdieselfde reeks rantsoene gevoer is. Verskille tussen skape enbokke ten opsigte van tempo van gasproduksie, glukosefermentasie, nitraat reduksie kapasiteit, totale vlugtige vetsuurproduksie en individuele vlugtige vetsuurkonsentrasie is veralgevind wanneer die inokulum verkry is van diere wat luserngevoer is. Die resultate dui aan dat verskillende metaboliesebane of groepe van mikro-organismes moontlik betrokke is indie twee herkouer spesies.Keywords: Rumen microenvironment, fermentation, goat-sheep,different quality dietsIntroductionSuperior biological efficiency has been claimed for thegoat (Fitzhugh, 1981) and its superior digestive efficiencyhas been mostly associated with utilization of plantstructural polymer (Gihad, 1976; Devendra, 1978) andwith a larger digestive capacity compared to sheep (Huston,1978). However, information on rumen function in thegoat is extremely scarce, especially in relation to degrad-ation of most of the soluble dietary components. Thepresent experiments were undertaken to study the com-parative behaviour of some of the rumen microenviron-mental measurements in relation to dietary components,and represent the initial stage of a systematic longtermstudy of the comparative rumen function of the goat.Experimental ProcedureMature Anglo Nubian crossbred goats and French Merinosheep fitted with permanent rumen cannulae were used inthree different trials. All the animals were confined inindividual crates during the entire experimental periodand were fed twice daily (9:00 and 16:00 hrs) at mainten-ance level, with free access to water during the eveningmeal.Trial IIn the first trial one goat (6 yr) and one sheep (8 yr)maintained on a uniform diet of good quality lucerne haywere used. Samples of rumen content (300g) were obtainedtwice a week 0, 2 and 4 hours after feeding. Rumen fluidwas obtained by filtration and pH and oxidation-reductionpotential immediately measured with a pH meter. Asample of rumen fluid was centrifuged at 3000 rpm for 5minutes and ammonium concentration was measured inthe supernatant by the Conway microdiffusion technique.The remaining supernatant was centrifuged at 27 000 g for45 min and utilized for the determination of osmoticpressure with an osmometer and total volatile fatty acids(VFA) by steam distillation. Equal volumes of the originalrumen fluid and Hungate buffer solution were mixed,gasified with CO2 and incubated at 39°C for one hour withor without 0,4% D( +) glucose. Total fermentation gasproduction was measured for one hour using a constantpressure manometric system. Nitrate reduction capacitywas measured in the presence of 0,06% NaNO) and 0,4%D( +) glucose by the phenoldisulphonic acid technique inthe 3000 rpm supernatant. Intraruminal, rectal and en-vironmental temperature were also measured 0; 2 and 4hours after feeding.Trial IIIn a second trial, lasting 5 months, two goats (6 yr) andtwo sheep (3,5 yr) were kept for one month on each of thethree diets decreasing in quality: Diet 1 - 100% of TDNrequirements provided by good quality lucerne hay; Diet2 - 50% of the requirements provided by lucerne hay and50% by wheat straw; Diet 3 - 100% of the requirementsprovided by wheat straw. There was a 15 day adaptationperiod between diets and all the feed was chopped andoffered using the same schedule as in the first trial. Totalfermentation gas production, pH, NH: -N and total VFA'swere measured in each animal at 0,1,2 and 5 hours afterfeeding. Whole rumen content samples were used insteadof rumen fluid for gas production measurements. Inaddition, population size and growth rate of rumen micro-organisms were measured at the same sampling times asdescribed by EI-Shazly and Hungate (1965). Mitoticindex and number of Langerhans cells in rumen epithelialcells were determined in 1 !lm toluidine blue stainedsections after fixation with glutaraldehyde and osmiumtetroxide and embedding in low viscosity Spurr epoxyresin. Rumen papillae biopsies were performed the firstday of the second and fourth week on each diet.Trial IIIIn a third trial, lasting 2 months, three goats (2 yr) andthree sheep (5 yr) were kept on a good quality lucerne haydiet as in the first trial. Total fermentation gas productionwas measured for one hour using samples of whole rumencontent obtained 0, 1,2,3,4 and 5 hours after feeding andincubated with Argon instead of CO2, Rumen gas sampleswere kept for CO2 -CH4 analysis and total and individualVFA's concentrations were measured in a 2.800 Varianchromatograph.Trial IRumen microenvironment measurements related to feedingestion were similar in both species. Oxido-reductionpotential, pH, osmotic pressure, NH: -N levels, VFA'sconcentration, temperature and DM content values werenot significantly different between goats and sheep at anyof the sampling times, excepting pH values at zero time(7,21 ± 0,11 and 7,38 ± 0,11, in the goat and sheeprespectively, p < 0,01). The fermentation gas productionrate and the nitrate reduction capacity of the rumen fluidare shown in Table 1. Gas production differed significantlybetween goats and sheep at each of the sampling times,values for goats always being higher than the values forsheep (133% higher at time 0 and 60% at 4 hours).However, when the incubation was carried out withglucose, values for sheep became higher than for goat's.Reduction capacity of the rumen content from goats wasalways lower than that of the sheep, this difference beingstatistically significant at zero and at two hours.Trial IIIn both species all the rumen measurements decreasedand changed their pattern as fermentable materials becameless available when the diet changed from lucerne hay towheat straw. Fermentation gas production rate, totalVFA's and NH: -N concentrations, microbial populationsize (all measured at maximum fermentation time) andmitotic index of the rumen epithelium, are shown inTable 2. The dramatic increase of gas production (aboutIS-fold) observed on the first diet at the point of maximumTable 1 Fermentation gas production rate, with or without added glucose andnitrate reduction capacity of rumen fluid from goat and sheepSampling time (h)Measurement Species 0 2 4Gas production Goat 2,80 ± 0,80' 9,60 ± 2,00 6,40 ± 0,80rate Sheep 1,20 ± 0,80 5,20 ± 1,20 4,00 ± 0,80(f!l·g-I·min-I) p<O,OO1 p <0,001 p<O,OOlGas production Goat 16,40 ± 3,60 20,40 ± 5,20 17,20 ± 1,60rate with 0,4% Sheep 20,00 ± 2,00 25,20 ± 2,80 23,20 ± 1,20Glucose p<0,05 p <0,05 p<O,OOl(f!!'g-I·min-I)NO) reduction Goat 2,01 ± 0,97 4,81 ± 1,48 3,61 ± 1,64capacity (mg %) Sheep 4,04 ± 1,22 6,96 ± 1,47 5,16 ± 1,04p<O,Ol p<0,02 N.S.'All values are the mean of 10 determinations ± SD.Table 2 Fermentation gas production rate, total VFA's concentration, NH;-Nconcentration, microbial population size and rumen epithelium mitotic indexin goats and sheep on three different diets*Measurement Species Diet 1 Diet 2 Diet 3Gas production Goats 15,42 ± 2,82" 10,57 ± 4,00 2,75 ± 1,21rate Sheep 13,92 ± 2,57 7,71 ± 1,35 1,54 ± 1,01(f!l.g -I.min -I) N.S. p<O,OO1 N.S.TotalVFA's Goats 107,98 ± 16,91 78,48 ± 10,51 33,10 ± 4,14concentration Sheep 101,22 ± 15,70 74,85 ± 5,36 36,61 ± 5,81(f!mol'ml-I) N.S. N.S. N.S.NH: -N concen- Goats 48,34 ± 7,86 26,45 ± 2,43 5,30 ± 1,24tration (mg %) Sheep 47,93 ± 5,64 22,56 ± 1,94 2,93 ± 1,06N.S. p<O,OO1 N.S.Microbial Goats 83,90 ± 7,67 56,60 ± 5,98 7,33 ± 1,56population size Sheep 70,00 ± 6,06 36,60 ± 3,32 3,33 ± 2,44N.S. p<0,05 p<O,OOlMitotic index Goats 0,28± 0,09 0,19 ± 0,D7 0,05 ± 0,04(%) Sheep 0,33± 0,08 0,28± 0,10 0,20 ± 0,11N.S. N.S. p<0,05'Values for first hour after feeding, excepting mitotic index."All values are the mean of 12 determinations ± SD.S.Afr .  J.  Anim. Sci .  1983, 13(3)fermentation activity, decreased concomitantly with thediet quality and almost disappeared on the third diet. Thismeasurement was always higher in goats and the dif-ferences between species increased as the diet qualitydecreased, this being statistically significant only for thesecond diet (50% lucerne hay and 50% wheat straw).Total VFA's and NHi - N concentration also decreasedin relation to changes in diet quality, showing no dif-ferences between species, excepting NH; -N on the seconddiet. Changes in microbial population size and growthindex closely followed the fermentation activity and theNH; -N concentration in both species. Rumen populationsize in the goats was significantly higher than in the sheepon the 2nd and 3rd diets. The decreasing availability offermentable substrate was also reflected in the mitoticindex and in the number of Langerhans cells of the rumenepithelium that also decreased with the diet quality.Tr ia l  l l lIn the third trial in which goats and sheep were fed withgood quality lucerne hay, differences between species inboth total fermentation gas production rate and totalVFA's production were clearly shown (Figure 1). Although0 tFigure 1 Fermentation gas production rate and total volatile fattyacids production of the rumen contents of goats and sheep on alucerne hay diet (Trial III).values before feeding were similar in both species, valuesafter feeding were markedly different especially two hoursafter feeding, values for goats being 65"h andZ2"h higherthan the gas and VFA's production values of the sheep(L7,42 + 1,95 vs 10,55 + I ,g3 pl .g- l .min-t  gas product ionand !24,38 + 1,92 vs 1.01.,76 + 2,33 pmol.ml-l VFA'sproduction). Individual VFA's molar percentages in thegoats were 7I,84;20,06 and 8,09 (for acetic, propionicand butyric acids respectively) which were similar to thevalues for sheep. The biggest difference in concentrationof individual VFA's was butyric acid which was found tobe 89% and 54"h higher at zero and two hours afterfeeding respectively in the goat as compared to the sheep.DiscussionUnder the experimental conditions described, all the215rumen microenvironmental analyses, followed a similarpattern in goats and sheep, at least up to the fifth hourafter feeding. Most of the measurements showed nosignificant differences between species. As goats andsheep moved to diets where the fermentable substrate inthe plant materials was less accessible, i.e. going fromlucerne hay to wheat straw, the rumen parameters changedsignificantly, but similarly, in both species, fermentativeactivity and microbial growth being affected together withNH; levels. Changes in total VFA's concentration in therumen were related to the proliferation rate of the cells ofthe rumen epithelium and in the number of Langerhanscells. Even though there were some differences betweenspecies, they were not very marked. On the other hand,rumen microenvironment of goats showed some clear cutdifferences from that of the sheep under good quality dietconditions, at least with respect to fermentation gasproduction, glucose fermentation, nitrate reduction ca-pacity, total VFA's production and individual VFA'sconcentrations. The results obtained suggest hat differentmetabolic pathways and/or groups of microorganismsmay be involved in the uti l ization of some of the solublematerials in the goat rumen microenvironment. Researchdesigned to explore this possibil i ty is currently in progressin our laboratory.AcknowledgementsSupported in part by Grant A-318179-82 from Departa-mento Desarollo Cientif ico, Universidad de Chile.ReferencesDEVENDRA, C. ,1978. The digestive efficiency of goats. WorldRev. Anim. Prod. 14,9.EL-SHAZLY, K. & HUNGATE, R.E., 1965. Fermentationcapacity as a measure of net growth of rumen microorganisms.Appl. Microbiol. 13,62.FITZHUGH, H.A., 1981. Small  ruminants as food producers.In: New Protein Foods (eds. A.M. Altschul and H.L. Wilcke),135. New York: Academic Press.GIHAD, E., I976. Intake, digestibility and nitrogen utilization oftropical natural grass hay by goats and sheep. J. Anim. Sci.43, 879.HUSTON, J.E., 1978. Forage utilization and nutrient requirementsof the soats. J. Dairv Sci. 61. 988.c.9I)!oL ;J 4 i.=Eoo cI L :3t!I;oFnoursou  1 6!o li  I  1 4rn --| [ -( D , c 1 2= E' ! :  T '  rn6  E D  t w- c +E j IblJ.hiE t ,

Rumen fermentative activity in the goat and sheep

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Rumen fermentative activity in the goat and sheep

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