Effects of pre-incubation in sheep and goat saliva on in vitro rumen digestion of tanniferous browse foliage

Hajer Ammar Raúl Bodas JESUS SALVADOR GONZALEZ SEGURA Abdelfattah Zeidan Mohamed Salem Javier Giráldez García (2013)

A two-stage in vitro procedure was used for assessing the activity of parotid saliva to enhance rumen digestion of tanniniferous browse foliage. The procedure consisted of pre-incubation in saliva for 4 h at 39 °C followed by incubation in diluted buffered rumen fluid. Using this procedure, a study was conducted to examine the effects of pre-incubation in sheep (SS), quebracho-supplemented sheep (qSS) and goat (GS) parotid saliva or in McDougall’s artificial saliva (AS, used as control) on in vitro rumen fermentation kinetics (estimated using the gas production technique) of browse foliage from six shrub species (Cytisus scoparius, Genista florida, Rosa canina, Quercus pyrenaica, Cistus laurifolius and Erica australis) collected over two seasons (spring and autumn), thus varying the in vitro digestibility (from 0·597 to 0·903) and tannin contents (from3 to 130 g tannic acid equivalent/kg dry matter (DM)). Saliva was collected from four sheep and four goats fed alfalfa hay, and fromfour sheep fed the same alfalfa hay but supplemented with quebracho (rich in condensed tannins) for 60 d, through a cannula inserted in the parotid duct, and rumen fluid was always from sheep fed alfalfa hay. The extent of degradation when browse foliage was pre-incubated in qSS was similar to that observed with control AS (0·449 v. 0·452, respectively), and 8% less than the value with pre-incubation in SS (0·490). In vitro fermentation kinetics (gas production parameters) of browse foliage were not significantly enhanced with pre-incubation in qSS compared with SS, whereas in vitro digestibility and extent of degradation in the rumen were significantly reduced with qSS compared with SS. After pre-incubation in sheep and goat saliva, the extent of browse foliage degradation was significantly increased by 4–8% compared with pre-incubation in the control AS. Fermentation efficiency of browse foliage was increased (P<0·05) with pre-incubation in GS compared with SS. Sheep or goat saliva may have some activity to affect in vitro rumen fermentation of the foliage samples incubated, enhancing extent of degradation of tannin-rich browse. However, a relationship between the magnitude of this effect and the tannin content of the browse foliage could not be established, suggesting that sheep and goat saliva may not be particularly important in neutralizing tannins.

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Effects of pre-incubation sheep goat saliva in vitro rumen digestion tanniferous foliage CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Nutritive evaluations of some browse tree foliages during the dry season: Secondary compounds, feed intake and in vivo digestibility in sheep and goats

Abdelfattah Zeidan Mohamed Salem Mounir El Adawy Peter Robinson (2005)

Four browse tree foliages (Cassia fistula, Schinus molle, Chorisia speciosa and Eucalyptus camaldulensis), native to the semi-arid region of north Egypt, were harvested during the dry season and evaluated for nutritional quality by determination of levels of nutrient and secondary compounds, as well as feed intake and apparent digestibility in sheep and goats. The study consisted of four experiments conducted in sequential 28-day periods that were the same in all respects, except that a different foliage was evaluated in each experiment which used six adult male Rhmani sheep (35±2.3 kg body weight (BW) at the start of the study) and six crossbred goats (30±1.56 kg BW). Sheep and goats were randomly divided into two groups of three and offered foliage at a level equal to 1.3 of the previous days voluntary intake of fresh matter and a commercial concentrate, with or without 10 g/animal/d of PEG, at 10 g/kg of BW to meet 0.7 of maintenance metabolizable energy requirements. Foliage crude protein (CP) content ranged from 124 (S. molle) and 128 (C. speciosa) to 185 g/kg DM (C. fistula). Ether extract was highest (97 g/kg) in S. molle. C. fistula had the lowest neutral detergent fiber (NDFom), acid detergent fiber (ADFom) and acid detergent lignin (lignin(sa)), while E. camaldulensis had the highest values. Total phenolics (TP), condensed tannins (CT), saponins (SAP), alkaloids (ALKA), the aqueous fraction (AF) of lectins, polypeptides and starch, and essential oils (EO) were lowest in C. speciosa (29, 21, 3, 0, 4 g/kg DM and 0.40 ml/kg DM, respectively) and highest in E. camaldulensis (102, 68, 15, 5, 3 g/kg DM and 15 ml/kg DM, respectively). Levels of TP, CT, SAP, ALKA and EO were highly positively intercorrelated among foliages, although AF was weakly negatively correlated to all others. Goats consumed 3.9% more foliage dry matter (DM) than sheep per kg BW0.75, and their digestibility was about 8% higher, probably reflecting their better capacity to detoxify secondary compounds in the rumen than sheep. Levels of CT (and due to its correlations, also TP, SAP, ALKA and EO) was a strong predictor of DM intake of PEG unsupplemented foliages within both sheep and goats. PEG increased (P<0.05) intake of DM and its components in sheep and goats. Digestion of DM and NDFom were not affected by feeding PEG, although digestion of OM, EE and CP were higher (P<0.05). TP in tree foliages (and due to its correlations, also CT, SAP, ALKA and EO) was not a predictor of the proportional increase in DM with PEG feeding, which was best predicted by level of CP within foliage. Overall, C. speciosa, had the highest nutrient value for both sheep and goats, both without and with PEG feeding, S. molle and C. fistula were intermediate and E. camaldulensis had the lowest nutritive value.

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Foliage Secondary compounds Feed intake Digestibility Sheep Goats CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA