Comparison between in situ dry matter degradation and in vitro gas production of tannin-containing leaves from four tree species

Dry matter (DM) degradation of Glycrrhiza glabra L, Arbutus andrachne, Juniperus communis, and Pistica lentiscus was determined using two different techniques: (i) the in vitro gas production and (ii) the in situ nylon bag degradability technique. Samples were incubated in situ and in vitro for 3, 6, 12, 24, 48, 72 and 96 h. In situ and in vitro DM degradation kinetics were described using the equation y = a + b (1 - e ct). At all incubation times except 3 and 72 h the cumulative gas production of J. communis was significantly lower than that of G. glabra, A. andrachne and P. lentiscus. At 3, 6 and 12 h incubation times the DM disappearance of J. communis was only significantly lower than that of P. lentiscus. At 24 and 48 h incubation times DM disappearance of J. communis was significantly lower than that of A. andrachne and P. lentiscus. There were significant relationships between in vitro gas production and in situ DM disappearance at 24 h and 96 h incubation times. The gas productions at 24 and 96 h incubation explained 51.2 and 52.4% of variation of DM disappearance, respectively. Gas production from the insoluble fraction (b) alone explained 66.4% of the variation of effective DM degradability (EDMD). The inclusion of gas production from quickly soluble fraction (a) and rate constant (c) of gas production in the regression equation did not improve the accuracy of predicting EDMD. It was concluded that in situ DM disappearance parameters of tannin-containing tree leaves such as used in this present study may be predicted from in vitro gas production parameters. South African Journal of Animal Science Vol. 34(4) 2004: 233-24

Raw and heat-treated culban (Vicia peregrina) seed as protein source for mirror carp (Cyprinus carpio) fingerlings

An 80-day feeding trial was conducted in a recirculation system aquarium operating at 26 ± 0.3 °C, to evaluate the nutritive value of Vicia peregrina seed as a possible protein source in the diet of mirror carp (Cyprinus carpio) fingerlings. Vicia peregrina seed was included in the diets at different levels, viz. 100, 200, 300 g heat-treated and 100, 200, 300 g raw seed in experimental diets designated A1, B1, C1, A2, B2 and C2, respectively. Growth parameters of the fish fed these diets were compared to fish receiving a fish meal and soyabean meal based control diet. On the basis of the specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER), the control and diets A1, B1, C1 and A2 were similar and significantly better than diets B2 and C2. Fish fed diets B2 and C2 showed a lower growth performance compared to those fed diets A1, B1, C1 and A2. Whole body fat content of the fish fed the diets containing the higher levels (>10%) of raw V. peregrina was significantly lower than in fish in the other treatments. Vicia peregrine seed has a potential as an alternative feed ingredient. It can be used without any adverse effects at up to 10% of the diet as a protein source in diets for fingerling mirror carp. However, the seed should be heat-treated if inclusion rates are to exceed 10% of the diet. Keywords: Culban, Vicia peregrina, nutritive value, heat treatment, mirror carp, growth South African Journal of Animal Science Vol. 36 (4) 2006: pp. 235-24

Partial replacement of fish and soyabean meal protein in mirror carp (Cyprinus carpio) diets by protein in hazelnut meal

An 80-day feeding trial was conducted as two experiments to evaluate the effects of replacement of fish meal (FM) and soyabean meal (SBM) protein with hazelnut meal (HM) protein in the diets of mirror carp (Cyprinus carpio) fingerlings. Growth parameters and body composition were measured in fingerlings cultured under laboratory conditions in a recirculation system aquarium at 26 ± 0.3 °C. In Experiment I four isonitrogenous, isoenergetic diets were formulated by replacing 0, 25, 35 and 45% of protein from FM by HM. Fingerlings receiving the diets in which 0, 25 and 35% of the FM protein were replaced, had similar body weights, specific growth ratios (SGR), protein efficiency ratios (PER) and feed conversion ratios (FCR). In Experiment II four isonitrogenous, isoenergetic diets were formulated by replacing 0, 20, 40 and 60% of protein in SBM with HM. Fingerlings receiving the diets where 0, 20 and 40% of the SBM protein were replaced, had similar body weights, SGR, PER and FCR. However, fingerlings consuming the highest dietary inclusion level of HM (60% replacement) had significantly lower responses for all the above parameters than fingerlings receiving the other diets. The fat content of fingerlings fed diet FM3 where 45 % of FM protein was replaced by HM protein, was significantly lower than those on the other diets. It was concluded that HM could replace up to 35% of the protein in FM and 40% of protein supplied by SBM in fingerling carp diets without adverse effects on growth, FCR, PER, FI, BWG and body composition. Keywords: Fish, hazelnut meal, fish meal, soyabean meal,Cyprinus carpio,aquaculture South African Journal of Animal Science Vol. 37 (1) 2007: pp. 35-4

Effect of heat treatment on in situ rumen degradability and in vitro gas production of full-fat soyabeans and soyabean meal

The objective of this study was to determine the effect of the heat treatment of full-fat soyabean (FFSB) and solvent extracted soyabean meal (SBM) on the in situ dry matter (DM) and protein degradability, and in vitro gas production kinetics of the protein sources. Ruminal disappearance of DM and crude protein (CP), and in vitro gas production were determined after 0, 4, 8, 16, 24, 48 and 72 h incubation using the in situ ruminal degradation and in vitro gas production techniques, respectively. In situ DM and CP disappearances were fitted to the exponential equation p = a + b (1-e-ct), where a is the rapid degradable fraction and b is the slow degradable fraction. In vitro gas production data were fitted to the equation, y = A {1 – exp [- b (t-T) – c (√t - √T)]}. Where b and c are the initial gas production rate constant (h-1) and later gas production rate constant (h-1/2), respectively. The two protein sources were heat treated both with steam pressure in an autoclave at 120 °C and in an oven at 150 °C for 20 min. Heat treatment had a significant effect on effective DM degradability (EDMD), effective CP degradability (ECPD) and in vitro gas production. Although the heat treatments reduced the EDMD, ECPD and the amount of gas produced, the results were inconsistent between protein sources. The heat treatments applied in the autoclave and the oven reduced the ECPD0.02 of FFSB by 12.5% and 10.9%, respectively. On the other hand, heat treatment applied through the autoclave decreased the ECPD0.02 of SBM by 13.9%, but by 18.7% when heat was applied through the oven. Heat treatment of SBM using the oven seemed to be more effective than using autoclaving. Heat treatments in the autoclave and oven reduced the total gas production from FFSB by 7.25 and 7.32%, respectively, and from SBM by 12.69 and 7.91%, respectively. It was concluded that heat treatment is an effective method of altering the rumen degradation characteristics of DM and CP in SBM and FFSB. Both methods could be used to increase the proportion of the rumen non-degradable protein fraction in protein sources which would then reach the small intestines unaffected by ruminal fermentation. Keywords: Full-fat soyabean; soyabean meal; heat treatment; in situ protein degradation; in vitro gas production South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.186-19

Effect of cultivar and formaldehyde treatment of barley grain on rumen fermentation characteristics using in vitro gas production

The aim of this study was to determine the effects of cultivar and formaldehyde treatment of barley grains on rumen fermentation characteristics using the in vitro gas production technique. Amount of gas produced (mL/g organic matter (OM)) during fermentation was determined after 0, 3, 6, 12, 24, 48, 72 and 96 h of incubation in buffered rumen fluid. The gas production kinetics were described using the equation: y = A {1 – exp [- b (t-T) – c (√t - √T)]} where b and c are the initial gas production rate constant (h-1) and later gas production rate constant (h-1/2), respectively. Cultivar and formaldehyde treatment had significant effects on gas production kinetics. Total gas production (A) ranged from 389.9 to 410.8 (mL/g OM) with the cultivar, Esterel, producing the largest volume of gas of the cultivars. Due to low gas production rates at 3, 6 and 12 h of incubation the cultivars, Viva and Cecilla, took the longest to produce 50% of their total volume of gas. Formaldehyde treatment reduced the rate (μ) of gas production at 3, 6 and 12 h of incubation, and the total volume of gas (A), but increased the time (h) to produce 50% of A and reduced the time (h) to produce 95% of A. The reduction in gas production ranged from 33.3 to 51 mL/g OM with 6 h incubation showing the highest decrease in gas production. It is concluded that formaldehyde treatment may provide an opportunity to manipulate the site of digestion of barley grain in the digestive tract of ruminants. Through the selection of suitable cultivars and through formaldehyde treatment the nutritional and health problems associated with the fermentation of barley grain in the rumen could be reduced. Keywords: Barley cultivars; formaldehyde treatment; gas production kinetics South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.206-21

The effect of polyethylene glycol (PEG 8000) supplementation on in vitro gas production kinetics of leaves from tannin containing trees

The objective of this study was to determine the effect of inclusion of polyethylene glycol (PEG 8000) during in vitro incubation on gas production kinetics, organic matter digestibility (OMD) and the metabolisable energy (ME) content of foliage from the tannin containing tree species, Pistica lentiscus, Arbutus andrachne and Juniperus communis. The amount of gas produced when the foliage was incubated with buffered rumen fluid, was determined after 0, 3, 6, 12, 24, 48, 72 and 96 h of incubation in the presence of PEG at inclusions rates of 15, 30, 60 and 90 mg and in the absence of PEG. Their kinetics were described using the equation p = a + b (1-e-ct). Addition of PEG resulted in an increased gas production at almost all incubation times in all tree species. However species showed variable responses. After 3 h of incubation the PEG addition showed no significant effect on gas production when the foliage from A. andrachne was incubated, but had a significant effect on gas production as duration of incubation extended. The increase in gas production in response to increased levels of PEG inclusion was linear for P. lentiscus and J. communis. However, when the PEG inclusion rates exceeded 60 mg there was no significant increase in gas production when A. andrachne was incubated. The estimated parameters such as gas production rate(c) and gas production (a) from the immediately soluble fraction were not affected by the level PEG treatment, except that PEG addition at 90 mg had a significant effect on the gas production (a) from immediately soluble fraction of leaves of J. communis. Gas production (b) from the insoluble fraction (mL) and potential gas production (a+b), OMD and ME of tree leaves increased significantly with increasing levels of PEG addition. However, when PEG inclusion exceeded 60 mg these parameters showed no significant increase when leaves from A. andrachne were incubated. Although the mean increase in OMD per mg PEG supplementation was 0.131 digestibility units, the increase in ME per mg PEG supplementation was 0.0201 ME units. The elevated levels of gas produced, and increased OMD and ME estimates with the inclusion of PEG demonstrated the negative effect of tannins in foliage on digestibility. South African Journal of Animal Science Vol. 35(4) 2005: 229-23

Availability of starch and other nutrients from maize grains or silages

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN033334 / BLDSC - British Library Document Supply CentreGBUnited Kingdo