Browsing by Author "Min, Byeng-Ryel"
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- ItemThe effect of condensed tannins upon protein degradation in the rumen and on animal production in sheep fed fresh Lotus corniculatus : a thesis in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Institute of Food, Nutrition and Human Health, College of Sciences at Massey University(Massey University, 1999) Min, Byeng-RyelA series of in vitro, in sacco and in vivo indoor and grazing experiments were conducted at Massey University and AgResearch Grasslands, Palmerston North, New Zealand to study the effect of condensed tannins (CT) in Lotus corniculatus (Birdfoot trefoil; CV. Grasslands Goldie) upon protein digestion in the rumen and on animal production. Aspects studied included effects of CT upon proteolytic bacterial activity, protein solubilization and degradation in the rumen and wool production and reproduction in grazing sheep. The studies also investigated the potential of L. corniculatus compared with perennial ryegrass/white clover pasture (hence referred as to pasture). The nutritional effects of CT in L. corniculatus were assessed by administrating polyethylene glycol (PEG; MW 3500) into the rumen of one group of sheep (PEG sheep; CT-inactivated), whilst a separate group of sheep received water (control sheep; CT-acting). PEG selectively binds with CT, preventing the CT from binding plant proteins in the rumen, so that effects of CT can be determined by comparing CT-acting sheep with PEG sheep. The productivity of mixed age ewes in grazing trials was measured in two experiments in the summer of 1995/1996 (Chapter 2) and the summer/autumn of 1997 (Chapter 3), to evaluate the effects of CT in L. corniculatus upon efficiency of animal production. A rotational grazing system with restricted feed allowance was used in both experiments. 1. During 1995/1996 (Chapter 2), a grazing trial was conducted to evaluate the effect of CT in L. corniculatus on wool growth and on wool processing characteristics in sheep fed close to maintenance for 125 days during summer and autumn (20 December 1995 until 25 April 1996). Half the ewes received twice daily supplements of PEG. The Lotus corniculatus contained 32 g total nitrogen (N) and 28 g total CT/kg dry matter (DM) and had an in vitro organic matter digestibility of 0.70. Action of CT reduced rumen ammonia concentration (P < 0.05) and reduced blood plasma urea concentration (P < 0.01) but increased blood plasma cysteine concentration (P < 0.05) compared to their counterparts receiving PEG supplementation. The concentration of blood plasma methionine was unaffected by CT. The CT had no effect on voluntary feed intake (VFI) and average liveweight gain (P > 0.05) but increased both clean fleece weight (P < 0.05) and staple length (P < 0.001). The CT also reduced dag percentage (P < 0.05) and tended to reduce wool yellowness (P = 0.07) relative to sheep receiving PEG. There were no significant effects of CT on fiber diameter (µm), staple breaking force (Newtons), bulk density (cm3/g) or wool resilience (cm3/g). It was concluded that the action of CT in sheep fed L. corniculatus increased the efficiency of wool production, with more wool being produced at the same feed intake. 2. Another grazing trial (Chapter 3) was conducted to study the effects of CT in L. corniculatus upon VFI, concentration of plasma metabolites, reproductive efficiency and wool production in ewes during two synchronised oestrous cycles in autumn 1997. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad-libitum for the last five days before ovulation. The experiment was of 2 x 2 factorial design, using two types of forage (L. corniculatus vs. pasture), with half the ewes grazing each forage being given twice daily oral PEG supplementation. A rotational grazing system with 200 mixed aged dry ewes (52±0.88 kg/ewe) was used. The Lotus corniculatus contained 17 g total CT/kg DM in the diet selected, with only trace amounts of total CT present in pasture. Ewes grazing L. corniculatus had higher plasma concentrations of branched chain amino acids (BCAA; 57 %) and essential amino acids (EAA; 52 %) than sheep grazing pasture. Again CT in L. corniculatus had no effect on mean VFI. The PEG supplementation had no effect upon ovulation rate (OR; 1.33 vs. 1.35) and lambing percentage (1.36 vs. 1.36 %) of the ewes grazing pasture. The CT increased both OR (1.78 vs. 1.56) and lambing percentage (1.70 vs. 1.42%) in the ewes grazing L. corniculatus relative to sheep supplemented with PEG. Increases in OR and lambing % of ewes grazing L. corniculatus were due to increases in fecundity (more multiple ovulations and less single ovulations), with no effect on ewes cycling/ewes mated. Compared to ewes grazing pasture, ewes grazing L. corniculatus had increased clean fleece weight (19 %). It was concluded that action of CT in the lotus diet was partly responsible for the increased efficiency of reproduction, with more lambs being produced at the same VFI. 3. In situ and in vitro rumen incubations (Chapter 4) were used to determine the effect of CT on both the solubilization and degradation of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39; fraction 1 leaf protein) from white clover (Trifolium repens; 0.3 g CT/kg DM) and Lotus corniculatus (22.1 g CT/kg DM). The sheep used for the experiments were fed either white clover or L. corniculatus. The loss of DM and neutral detergent fibre (NDF), total N and Rubisco from polyester bags suspended in the rumen of sheep was used as a measurement of solubilisation. The effect of CT extracted from L. corniculatus on the degradation of Rubisco from white clover was measured by in vitro incubations with rumen fluid obtained from the same fistulated sheep fed either white clover or L. corniculatus. In the absence of PEG, the solubilisation of Rubisco from L. corniculatus was less rapid than the solubilisation of this protein from white clover when each forage was incubated in the rumen of sheep fed the same diet. Addition of PEG tended to increase the solubilisation of Rubisco from L. corniculatus, suggesting that CT slowed the rates of solubilization of Rubisco from this forage. The action of CT did not inhibit the in situ loss of NDF from either white clover or L. corniculatus. In the absence of PEG, the in vitro degradation of Rubisco from L. corniculatus was slower when compared to the degradation of this protein from white clover; PEG addition increased the degradation of Rubisco from L. corniculatus, but not from white clover, showing that CT was the causal agent. The addition of CT extracted from L. corniculatus markedly depressed the degradation of Rubisco from white clover, with the effect being completely reversible by PEG. The large subunit (LSU) of Rubisco was consistently degraded at a faster rate than the small subunit (SSU) and added CT had a greater effect in slowing the degradation of the LSU compared to the SSU. It was concluded that the action of CT from L. corniculatus reduces the digestion of protein in the rumen of sheep through a minor effect on solubilization and a major effect on degradation. The main effects of CT on protein solubilization and degradation seemed to be produced locally by CT present in plant tissue. 4. Eleven strains of proteolytic rumen bacteria (Chapter 5) were used to determine the effect of CT extracted from Lotus corniculatus on the in vitro proteolysis of Rubisco protein, bacterial specific growth rate and maximum optical density (ODmax). Effects of CT on the rate of Rubisco proteolysis (%/h) were determined through making measurements in the presence and absence of PEG. Streptococcus bovis strain NCFB 2476 and B315, Butyrivibrio fibrisolvens strain WV1 and C211a, Prevotella ruminicola strain 23 and C21a, Clostridium proteoclasticum B316T, Ruminococcus albus 8, Fibrobacter succinogenes S-85, Eubacterium sp. strain C12b and C124b were tested against 1.5 mg CT/ml for Rubisco proteolysis and were examined with 0, 50, 100, 200, 400, and 600 µg CT/ml for bacterial growth measurements. In general, the presence of CT markedly depressed the degradation of both the LSU and SSU of Rubisco, with the effect being completely reversible by PEG. However, the rates of proteolysis per hour for both sub-units of Rubisco varied considerably between individual bacterial species and subunits of Rubisco. In the absence of CT, S. bovis strain NCFB 2476 and B315 and P. ruminicola like-strain C21a appeared to be most active in both LSU and SSU degradation, while P. ruminicola 23, Eubacterium sp. strain C12b and C124b, C. proteoclasticum B316T, B. fibrisolvens strain WV1 and C211a had moderate to lower rates of LSU and SSU degradation. In the presence of CT, S. bovis strain NCFB 2476 and B315 and P. ruminicola-like strain C21a appeared to be most active in both LSU and SSU breakdown. Most bacterial strains showed significantly (P< 0.05-0.01) decreased specific growth rate and ODmax with increasing CT concentrations. However, some of the strains, C. proteoclasticum B316T and R. albus 8 showed transient increases in specific growth rate at low concentrations of CT (between 50 to 100 µg CT/ml), but not at high concentrations of CT. In terms of specific growth rate, addition of CT at low concentrations (50-200 µg CT/ml), S. bovis NCFB 2476, Eubacterium sp. C124b and F. succinogenes S-85 were most affected compared to the minus CT controls, while P. ruminicola sp. C21a and C. proteoclasticum B316T were not greatly inhibited at the highest concentrations of CT. The degree of inhibition of both bacterial growth and Rubisco degradation in the presence of CT varied considerably between individual bacterial species and will be discussed in Chapter 5. It was concluded that action of CT from L. corniculatus reduces both the rate of Rubisco proteolysis and the growth rate of proteolytic rumen bacteria, but the magnitude of the CT effect differed between strains used. 5. Twelve six month old Romney sheep were fistulated in the rumen and abomasum and fed Lotus corniculatus (32 g CT/kg DM), to examine the effects of CT on proteolytic rumen bacterial populations and on quantitative N digestion in the rumen. Half the animals were given continuous intraruminal infusions of PEG. In the first part of the experiment, the populations of four proteolytic rumen bacteria were enumerated directly from rumen samples using a competitive polymerase chain reaction (cPCR) technique. During pre-feeding on a perennial ryegrass/white clover pasture diet, populations of C. proteoclasticum B316, Eubacterium sp. C12b, S. bovis B315 and B. fibrisolvens C211a were 1.6 x 10 8, 2.7 x 10 8, 7.1 x 10 6 and 1.2 x 10 6 per ml respectively. When the diet was changed from pasture to L. corniculatus (average of 8 h to 120 h), the average populations of C. proteoclasticum B316, Eubacterium sp. C12b, S. bovis B315 and B. fibrisolvens C211a from the same animals were decreased significantly (P < 0.001) to 5.1 x 10 7, 1.5 x 10 8, 2.6 x 10 6 and 1.0 x 10 6 per ml, respectively. When the PEG was infused into the rumen of sheep fed L. corniculatus, the populations of proteolytic bacteria were significantly increased (P < 0.01-0.001) compared to the CT-acting group. Rumen proteinase activity, concentrations of rumen ammonia and soluble N were decreased significantly (P < 0.05-0.001) in the CT-acting compared to the PEG treatment group. In the quantitative N studies, the principal effects of CT were to reduce rumen N digestibility (P < 0.05) and ammonia pool size, and to increase the flow of non-ammonia nitrogen (NAN) to the abomasum. Dry matter intake and DM digestibility were unaffected. The N intake, rumen NAN and microbial NAN pool sizes were similar in both CT-acting and PEG sheep. Non-microbial NAN fluxes to the abomasum were significantly higher (P < 0.01) in the CT-acting sheep than in the PEG sheep, but microbial NAN flux to the abomasum was unaffected by treatment. It was concluded that L. corniculatus CT reduced forage protein degradation in the rumen, and increased the flow of undegraded feed NAN to the abomasum. Proteolytic bacterial populations seemed to be reduced by CT, but these changes did not effect the total rumen microbial NAN pool or abomasal microbial NAN flux. Therefore, more protein was potentially available for absorption from the small intestine. 6. This study is the first to report that action of CT increased reproductive efficiency in grazing ewes. It is also the first study to show that action of CT decreased proteolytic bacterial populations measured directly from rumen samples using cPCR techniques. Feeding forages containing CT such as L. corniculatus has been shown to reduce proteolysis in the rumen, with the mechanisms being to slightly reduce protein solubilization, to markedly reduce protein degradation and to reduce the populations of proteolytic bacteria. CT increased NAN flux into the abomasum (in indoor studies) and increased animal production in grazing ewes without affecting VFI, thus improving the efficiency of animal production. It is concluded that forage CT can be used to increase the efficiency and sustainability of livestock production from grazed forages.
- ItemVenison and velvet production from Red and hybrid deer by one year of age : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University, New Zealand(Massey University, 1996) Min, Byeng-RyelA grazing experiment was conducted at Massey University Deer Research Unit, Palmerston North, New Zealand during 1995, to study the effects of grazing chicory (Cichorium intybus), Lotus comiculatus and perennial ryegrass (Lolium perenne)lwhite clover (Trifolium repens) pasture upon the growth, voluntary feed intake (VFI), venison and velvet production of red and hybrid (0.75 red;0.25 elk) deer from weaning to slaughter at one year of age. The animals were randomly allocated to graze either chicory, lotus or pasture and grazed these forages during autumn and spring using a rotational grazing system, with each group balanced for genotype and sex. All groups were joined to graze pasture during winter, when chicory and lotus were dormant. 1. Few animals attained the target slaughter weight (50kg carcass or greater) when grazing pasture and spiker velvet antler weight was low at approximately 0.2 kg per stag. 2. In this study the greatest advantages obtained for specialist forages were for chicory. Carcass weight of deer grazing chicory was higher than for deer grazing pasture, due mainly to increasing autumn LWG and dressing-out percentage at slaughter, with a smaller response in spring LWG. The largest carcass weights were consistently obtained from hybrid stags grazing on chicory, with values for red deer and hybrid stags being 56.0 and 59.3 kg when grazed on chicory and 48.6 and 53.3 kg respectively when grazed on pasture. Chicory had a higher organic matter digestibility (OMO) and VFI than pasture during autumn but similar values in spring, accounting for its autumn growth stimulation. Carcass subcutaneous fat depth (GR) was higher for deer grazing chicory than pasture, but after being adjusted to equal carcass weight, there was no difference in GR measurement. Relative to deer grazing on pasture, grazing on chicory increased total spiker velvet antler production (323 v 225 g/stag), by advancing the dates of pedicle initiation (18 days), velvet antler initiation (24 days), and first velvet cutting (17 days) and increasing the rate of velvet antler length growth. Initiation of velvet growth was correlated with liveweight, with each 10 kg increase in liveweight advancing the dates of pedicle initiation, commencement of velvet growth and first velvet cutting by 10, 18 and 13 days respectively. Correction of the data to equal liveweight removed a component of the advancement produced from feeding on chicory, but an effect still remained due to chicory feeding per se. It was concluded that grazing chicory not only increased carcass weight (especially in hybrid stags), but also increased velvet antler production. This was achieved by increased VFI and increased OMO of chicory in autumn, relative to deer grazing pasture, and probably by increased absorption of protein and minerals in deer fed chicory. 3. OMO of lotus was higher than that of pasture during autumn, but not in spring. The OMO of either chicory or lotus showed little change between seasons, but pasture changed with the season, being of lowest OMO in autumn and highest OMO in spring. 4. Responses to deer grazing lotus were limited by the reduced number of grazing days that could be achieved, due to problems in lotus establishment. In spite of these problems, grazing lotus (48 gCT/kg OM) did increase the LWG of stags during autumn (248 v 176 g/day) and increased the efficiency of growth in spring, with LWG being similar to deer grazing pasture, but VFI being lower (1.53 v 2.00 kgOM/day) for lotus compared to pasture. Although deer grazing lotus had a similar carcass weight compared to deer grazing pasture, dressing-out percentages of deer grazing lotus were higher than that of deer grazing pasture (56.4 v 53.2 %). The carcass GR tissue depth of deer grazing lotus had similar values compared to pasture. There was no interaction between forage and genotype for carcass weight and dressing out percentage. Stags grazing lotus did not show any advancement in dates of pedicle initiation, velvet antler initiation and weight of velvet production compared to stags grazing pasture. 5. Total condensed tannin (CT) concentration in lotus was 48 and 13 g/kgOM in hand plucked and oesophageal fistulae (OF) extrusa samples respectively. Most CT in hand plucked lotus samples was extractable, with much smaller amounts being protein-bound or fibre-bound. Extractable CT was not detected in lotus OF extrusa samples, and the concentration of protein-bound and fibre-bound CT remained similar to hand plucked samples. Therefore, after chewing during eating, the extractable component of CT in lotus feed could not be extracted and detected by the Butanol/HCI analysis methods and may have been bound to deer salivary proteins. Total CT in both hand plucked and OF extrusa samples was 3.1 v 5.8 g/kgOM for chicory and 0.3 v 1.5 g/kgOM for pasture. As a result, chewing (in OF samples) did not reduce the CT content of pasture or chicory. This may be due to the low concentration of extractable CT (and high proportions of bound CT) in these forages, which may have limited access for the deer salivary CT-binding proteins. 6. Overall it was concluded that chicory was of very high feeding value (FV) and had excellent nutritional advantages for increasing deer production. However, crops of chicory need to have specialised grazing management to increase persistency. New chicory cultivars need to be selected to increase persistency and to reduce reproductive stem formation during summer. Effects of protein supply on initiation of pedicle and velvet antler development in weaner stags grazing fresh forages also needs to be studied. The small responses obtained in the present study give some indication that the CT content of Lotus comiculatus may have a number of values for improving the efficiency of growth in young deer. Further experiments are needed in this area.