Condensed tannins and nutrient utilization by lambs and goats fed low-quality diets

Nutrient digestibility, fecal output of fractionated proteins, and ruminal fermentation parameters of goats fed a diet supplemented with spent green tea and black tea leaf silage

Spent green and black tea leaf silage (GTS and BTS, respectively) was offered as a protein supplement to goats to examine in vivo digestibility, nitrogen balance, urinary excretion of purine derivatives, and ruminal fermentation. Four castrated goats were fed a basal diet supplemented with alfalfa hay cube (AHC), GTS, or BTS in a 4 × 4 Latin square design. Digestibilities of various nutrients except for nitrogen (N) fraction were unaffected by the type of supplement. Digestibility of acid detergent insoluble N (ADIN) in BTS treatment was a negative value and significantly lower than those in other treatments. Urinary N output and retained N were not significantly affected by the diets. The fecal output of neutral detergent insoluble nitrogen (NDIN) and ADIN in the BTS treatment was significantly higher than those in other treatments. Urinary excretion of purine derivatives was not affected by the treatments. Ruminal NH₃ -N concentration in AHC and GTS treatments were not significantly different, but that in the BTS treatment was significantly lower than others. These results indicated that GTS is substitutable for AHC as a protein supplement, whereas BTS was able to bind proteins tightly in the digestive tract, which lowered ruminal N degradability and increase fecal N output.

A review on the mechanisms of the effect of silymarin in milk thistle (Silybum marianum) on some laboratory animals

One of the most valuable medicinal plants is milk thistle (Silybum marianum) or martighal. An annual or biennial plant of the Asteraceae family and English name Milk thistle, a Matte green colour and prickly plant with a standing stem that can be thick, simple, or slightly branched (ramified). Its seeds contain about 70%-80% of the flavonolignans of silymarin and about 20%-30% of polymeric and oxidized polyphenolic compounds (such as tannins). Traditionally, the plant has been used to increase milk secretion, relieve menstrual cramps, lessen depression, decrease gallstones, and jaundice as well as improve functions of the liver, spleen, and kidney. This review reviews studies on the effects of adding milk thistle to quail diet. Consumption (0.5% and 1%) of milk thistle powder in the diet of Japanese quail significantly increased feed intake, body weight, and improved carcass components. Blood constituents including total protein and albumin were improved along with decreased HDL, ALT, and AST. The use of milk thistle levels (0.5% and 1.5%) significantly improved the antioxidant total of plasma. Consumption of silymarin in quail diet increased the number of white blood cells, calcium, vitamin D3, and albumin. Silymarin also decreased the relative weights of bursa of Fabricius and spleen. This review indicates that milk thistle can improve growth performance, feed conversion ratio, and immune system in quail.

Antinutritional factors in foods for livestock

Antinutritional factors in livestock foods may be defined as the substances which either by themselves, or through their metabolic products arising in the system, interfere with food utilization and affect the health and production of animals. These deleterious substances, also referred to as anti-quality factors can be divided tentatively into four groups based on their effects on livestock: (i) affecting protein utilization and depressing digestion (protease inhibitors, tannins, saponins, lectins, etc.), (ii) metal ion scavengers (oxalates, phytates, gossypol pigments, glucosinolates), (Hi) antivitamins, and (iv) those which cannot be put in the above categories (mycotoxins, mimosine, cyanogens, nitrates, alkaloids, photosensitizing agents, isoflavones, etc.). This paper discusses only those deleterious substances which are of prime concern to the farmers and scientists of developing countries. Much emphasis is given to polyphenols compounds, as this class of anti-nutritional factor is the most widespread in non-conventional foodstuffs, i.e. agroindustrial and forestry byproducts. The effective utilization of these non-conventional foods forms the main area of research in the third world countries due to shortages of conventional foods. Efforts have been made to present the current knowledge on their assay methods, effects on animals, mode of action and detoxification/detannification using physical, chemical and biotechnological approaches. Other anti-quality factors viz., mycotoxins, mimosine, cyanogens and nitrates which also cause damage to livestock in developing countries are also discussed briefly.

Different means of administering polyethylene glycol to sheep: effect on the nutritive value of Acacia cyanophylla Lindl. foliage

Polyethylene glycol-4000 (PEG) was used to inactivate tannins in Acacia cyanophylla Lindl foliage. In the first of two experiments, four groups of five Barbarine sheep were held in metabolism crates so that intakes, apparent digestibilities, nitrogen balances and urinary excretion of allantoin could be measured. The second experiment involved four groups of three male Queue Fine de l'Ouest sheep fitted with rumen cannulae and housed in individual pens to measure rumen fermentation parameters and dry matter in situ degradation of A. cyanophylla foliage. All animals received fresh A. cyanophylla foliage ad libitum and 330 g concentrate on a daily basis. In each experiment, three groups of sheep received 20 g PEG daily, either mixed with concentrate (PEG-concentrate), dissolved in drinking water (PEG-water) or sprayed as a solution on A. cyanophylla foliage at the point of feeding (PEG-treatment). The fourth group was not supplied with PEG (control). Dry-matter intake of A. cyanophylla was low (28·3 g/kg metabolic live weight (M0·75) per day) and increased in sheep given the PEG-concentrate diet (38·2 g/kg M0·75 per day). PEG-concentrate and PEG-water diets resulted in an improvement in protein utilization as indicated by an increase of crude protein apparent digestibility (2·1 and 1·9 fold, respectively), nitrogen retention (3·2 fold with both dietary treatments) and urinary excretion of allantoin (1·9 and 1·5 fold, respectively). Improvements obtained with PEG-treatment diet were low and in general not significant (P > 0·05). Low neutral-detergent fibre and acid-detergent fibre apparent digestibility coefficients of diets led to the conclusion that conventional detergent extraction techniques are questionable in determining the in vivo digestibility of cell wall constituents for tannin-rich forages. Results from rumen fluid analyses indicated that sheep given PEG-containing diets had higher ammonia-nitrogen and volatile fatty acid (VFA) concentrations (P < 0·05). These results, coupled with the increase of allantoin excretion gave clear evidence that the efficiency of microbial synthesis was improved with PEG addition. The absence of change in ruminal pH and molar proportions of individual VF A suggested similar fermentation patterns among all dietary treatments. PEG supply increased the slowly degradable fraction of A. cyanophylla foliage incubated in the rumen (P < 0·05), thus dry matter potential degradability (a + b) was highest in sheep given PEG-containing diets. It is concluded that the affinity of acacia tannins to PEG, increased the availability of degradable proteins, which resulted in an improvement of the nutritive value of acacia foliage. However, for practical situations, adding PEG to concentrate or to drinking water is recommended for sheep browsing A. cyanophylla trees in the field or fed indoors.

Effects of utilization of local food by-products as total mixed ration silage materials on fermentation quality and intake, digestibility, rumen condition and nitrogen availability in sheep

Four wethers were used in a 4 × 4 Latin square design experiment to evaluate in vivo digestibility of total mixed ration (TMR) silage with food by-products for dairy cows, and the ruminal condition and nitrogen (N) balance were examined. Five by-products (i.e. potato waste, noodle waste, soybean curd residue, soy sauce cake and green tea waste) were obtained. Four types of TMR silage were used: control (C) containing roughage and commercial concentrate, T1:20% and T1:40% containing the five by-products replacing 20% and 40% of the commercial concentrate on a dry matter (DM) basis, respectively, and T2:40% containing three by-products (potato waste, noodle waste and soybean curd residue) replacing 40% of the commercial concentrate on a DM basis. The ingredients were mixed and preserved in oil drum silos for 4 months. The TMR silages showed 4.02-4.44% and 1.75-2.19% for pH and lactic acid contents, respectively. The digestibility of DM and neutral detergent fiber, and total digestible nutrient content were higher (P < 0.05) for T2:40% feeding than for C feeding. Urinary nitrogen excretion tended to be lower (P = 0.07) for T2:40% than for C. The results suggested 40% replacing of commercial concentrate by using the three food by-products can be most suitable for TMR silage.

Meat odour and flavour and indoles concentration in ruminal fluid and adipose tissue of lambs fed green herbage or concentrates with or without tannins

A 2 × 2 factorial experiment was carried out to evaluate the effect of herbage or concentrate feeding system and tannin addition to diet on skatole and indole in ruminal fluid and adipose tissue and meat sensory properties. Twenty-eight male lambs aged 45 days were randomly assigned to one of two feeding systems (vetch green herbage or concentrates, n = 14) and within feeding system to one supplement (quebracho tannins added to the diet or none). Animals were kept in singular pens and slaughtered at the age of 105 days. Indole (P < 0.05) and skatole (P < 0.01) concentrations in ruminal fluid were higher in lambs fed herbage compared to those given concentrates. Skatole in ruminal fluid tended to be present at lower concentrations in animals that received the tannin supplementation (P = 0.07). Indole was also higher in the caudal fat of animals fed green vetch compared to those fed concentrate (P = 0.04). Skatole concentration was lower in the fat of lambs fed concentrates compared to those given herbage (P = 0.05) and was lower in the fat of animals supplemented with tannins compared to the animals not supplemented (P = 0.01). Sheep meat odour was lower in meat from animals supplemented with tannins compared to those not supplemented (P < 0.01). It is concluded that tannins are more effective in reducing skatole formation in ruminants when they are associated with concentrate diets than green herbages.

A comparative study of the effect of two-stage olive cake added to alfalfa on digestion and nitrogen losses in sheep and goats

This work was conducted to evaluate the effect of tannins, contained in a by-product derived from olive oil extraction (two-stage olive cake), on nutrient digestibility, nitrogen (N) losses and liver and kidney functions in goats and wethers. Six Segureña wethers and six Granadina goats were fed three experimental diets: alfalfa hay (AH); alfalfa hay and a concentrate (formulated with two-stage olive cake, barley and a mineral-vitamin mixture) without (AHCO) or with polyethylene glycol (PEG) addition (AHCOP). The inclusion of two-stage olive cake increased condensed tannins content of the diet and led to a decrease ( P < 0.001) in dry matter, organic matter, neutral-detergent fibre, acid-detergent fibre and crude protein (CP) digestibility. PEG supply increased ( P < 0.001) CP digestibility and N losses in urine and faeces only in wethers. Concentrations of creatinine and alkaline phosphatase activity, measured in the serum of animals, were not modified either by olive cake inclusion or by PEG supply. Results from this work indicate a higher sensitivity of sheep to diets containing condensed tannins, compared with goats, and reveal no toxic effect of tannins from two-stage olive cake at the concentration used in the experimental diets.

Qualidade da silagem de híbridos de sorgo em diferentes estádios de maturação

Avaliou-se a qualidade das silagens de três híbridos de sorgo, BRS 610, BR 700 e BRS 655, colhidos em três estádios de maturação da planta, grãos leitoso, pastoso e farináceo. O delineamento utilizado foi o inteiramente ao acaso, em esquema fatorial 3x3 (híbridos x estádios de maturação), com quatro repetições. Os teores de matéria seca apresentaram variação de 22,9% a 41,3%. O BR 700 apresentou maior porcentagem de matéria seca que os demais híbridos em todas as idades de corte. Os teores de proteína bruta e as frações fibrosas, fibra em detergente neutro e fibra em detergente ácido, apresentaram comportamento diferente entre estádios de maturação e entre híbridos. Os valores de lignina não foram alterados com o avanço da idade de corte. Os coeficientes de digestibilidade in vitro da matéria seca das silagens variaram de 50,7% a 55,6% e comportaram-se de forma diferente com a maturidade para cada hibrido. De acordo com os valores de pH, de nitrogênio amoniacal e de ácidos orgânicos encontrados, as silagens dos três híbridos são classificadas como de boa qualidade em todos os períodos de colheita.

The nutritive value of Acacia saligna and Acacia salicina for goats and sheep

Acacia saligna and A. salicina phyllodes, harvested in autumn from young and mature trees, were fed as sole diets to goats (20·3 (s.d. 4·8) kg; no. = 16) and sheep (32·6 (s.d. 4·9) kg; no. = 16). Crude protein of phyllodes from mature trees was 111 g/kg dry matter (DM) and from young trees ranged between 121 and 132 g/kg DM. Condensed tannins and ash content were about twice as high in young trees as in old ones and gross energy was higher in old trees than in young ones. DM intakes by goats from both tree species were low: 24·8 and 13·7 g/kg M0·75 per day for mature and young trees, respectively. Corresponding intakes by sheep were 20·4 and 11·5 g/kg M0·75 per day. Metabolizable energy intakes were up to 125 and 99 kj/kg M0·75 per day for goats and sheep, respectively and were higher for phyllodes from mature trees than for young trees. Goats lost up to 219 glday and sheep up to 346 g/day and both species were in negative nitrogen balance. DM, organic matter and energy apparent digestibilities were low for all diets but were generally higher for goats than sheep. It is concluded that neither A. saligna nor A. salicina could be used as a sole food for small ruminants because of low intakes and negative nitrogen balances. This appears to be due to high tannin content.

Difference in the nature of tannins on in vitro ruminal methane and volatile fatty acid production and on methanogenic archaea and protozoal populations

Six plant sources of hydrolyzable tannins (HT) or HT and condensed tannins (CT; designated as HT1, HT2, HT3, HT + CT1, HT + CT2, and HT + CT3) were evaluated to determine their effects in vitro on CH(4) production and on ruminal archaeal and protozoa populations, and to assess potential differences in biological activities between sources containing HT only or HT and CT. Samples HT1, HT2, and HT3 contained only HT, whereas samples HT + CT1, HT + CT2, and HT + CT3 contained HT and CT. In experiment 1, in vitro incubations with samples containing HT or HT + CT resulted in a decrease in CH(4) production of 0.6 and 5.5%, respectively, compared with that produced by incubations containing the added tannin binder polyethylene glycol-6000. Tannin also suppressed the population of methanogenic archaea in all incubations except those with HT2, with an average decrease of 11.6% in HT incubations (15.8, 7.09, and 12.0 in HT1, HT2, and HT3) and 28.6% in incubations containing HT + CT (35.0, 40.1, and 10.8 in HT + CT1, HT + CT2, and HT + CT3) when compared with incubations containing added polyethylene glycol-6000. The mean decrease in protozoal counts was 12.3% in HT and 36.2% in HT + CT incubations. Tannins increased in vitro pH, reduced total VFA concentrations, increased propionate concentrations, and decreased concentrations of iso-acids. In experiment 2, when a basal diet was incubated with graded levels of HT + CT1, HT + CT2, and HT + CT3, the total gas and CH4 production and archaeal and protozoal populations decreased as the concentration of tannins increased. Our results confirm that tannins suppress methanogenesis by reducing methanogenic populations in the rumen either directly or by reducing the protozoal population, thereby reducing methanogens symbiotically associated with the protozoal population. In addition, tannin sources containing both HT and CT were more potent in suppressing methanogenesis than those containing only HT.

Effect of polyethylene glycol 4000 supplementation on the performance of indigenous Pedi goats fed different levels of Acacia nilotica leaf meal and ad libitum Buffalo grass hay

In a first of two experiments, twenty yearling male Pedi goats weighing 21.3 +/- 0.5 kg live weight were used in a 37-day study in a 2 (levels of PEG 4000) x 2 (levels ofAcacia) Factorial arrangement in a Completely Randomised Design to determine the effect of the level of Acacia nilotica leaf meal supplementation plus 23 g polyethylene glycol 4000 on diet intake and digestibility, and growth rate of Pedi goats fed ad libitum Buffalo grass hay. Acacia nilotica leaf meal contained high amounts of total phenolics (2.04% DM) and low amounts of condensed tannins; both extracted (0.37% DM) and unextracted (1.83% DM). Supplementation with PEG 4000 increased (P < 0.05) crude protein intake as the level of Acacia nilotica leaf meal increased from 80 to 120 g. Similarly, treatment with PEG 4000 improved (P < 0.05) DM, OM and CP digestibilities when compared to 80 g Acacia nilotica leaf meal. Supplementation with PEG 4000 resulted in an increase (P < 0.05) in blood urea concentrations. Polyethylene glycol 4000 has the potential to improve the feeding value of A. nilotica leaf meal and can, therefore, be used in the feeding systems for ruminant animals. The second experiment determined the effect of A. nilotica leaf meal supplementation on in vitro digestibility of the diets similar to the actual ratios of the first experiment. Level of A. nilotica leaf meal supplementation plus 23 g PEG 4000 supplementation improved (P < 0.05) in vitro DM, OM and CP digestibilities where 120 g A. nilotica leaf meal was supplemented. Similarly, 23 g PEG 4000 supplementation also improved (P < 0.05) in vitro CP digestibility where 80 g A. nilotica leaf meal was supplemented. In vivo DM and OM digestibilities were best predicted from in vitro DM and OM digestibilities while in vivo CP was explained by in vitro OM and CP digestibilities. It is, therefore, concluded that in vitro DM and OM digestibilities have good capacity to predict in vivo DM and OM digestibilities while OM and CP digestibilities have good capacity to predict in vivo CP digestibility.

Effect of polyethylene glycol onin vitrodegradability ofnitrogen and microbial protein synthesis fromtannin-rich browse and herbaceous legumes

Determination of microbial degradability of N is important in formulating a sound supplementation strategy for efficient utilisation of basal as well as supplementary diet components.In vitrodegradability of N (IVDN) from tannin-containing browses (Acacia cyanophylla, Acacia albida, Acioa barteriandQuercus ilex) and two herbaceous legumes (Desmodium intortumandDesmodium uncinatum) was determined using thein vitrogas-production method coupled with NH3-N measurement in the presence and absence of a tannin-binding agent (polyethylene glycol (PEG), molecular mass 6000). Addition of PEG to tannin-containing feeds significantly (P< 0·05) increasedin vitrogas and short-chain fatty acid (SCFA) production, and IVDN. The use of PEG as a tannin-binding agent increased IVDN from 28 to 59, 32 to 72, 19 to 40, 32 to 73, 40 to 80, and 26 to 77 % inA. cyanophylla, A. albida, A. barteri,D. intortum,D. uncinatumandQ. ilexrespectively. There was significant correlation between total phenolic compounds (total phenol, TP; total tannin, TT) in leguminous forages and percentage increase in IVDN on addition of PEG (P< 0·05;R20·70 and 0·82 for TP and TT respectively). The difference in IVDN observed in the absence and presence of PEG indicates the amount of protein protected from degradation in the rumen by tannins. When measured after 24 h incubation, tannin-containing feeds incubated in absence of PEG resulted in higher microbial protein synthesis than in the presence of PEG. Addition of PEG significantly (P< 0·05) reduced the efficiency of microbial protein synthesis expressed as μmol purine/mmol SCFA.

Effect of polyethylene glycol on rumen volume and retention time of liquid and particulate matter along the digestive tract in goats fed tannin-rich carob leaves (Ceratonia siliqua)

The present work studied the effects of tannins in carob leaves (CL) on rumen volume and kinetics, and on the retention time of fluid and particulate components of the digesta along the gastrointestinal tract (GIT) in goats. The experimental design was a two factor crossover experiment, i.e. in phase 1, two goats were fed CL and 2 CL and polyethylene glycol (PEG) and in phase 2, the treatments were switched. The main effects of tannins were depression of the rumen fluid and particulate content of the rumen, acceleration of the passage of liquid from the abomasum, and delay of the passage of digesta in the intestine. The overall effect was a delay in the passage of fluid and particulate matter throughout the entire GIT. It is hypothesised that these responses are largely the consequence of the interaction of tannins with digestive enzymes and the epithelium lining of the digestive tract.

Silagem de sorgo de porte baixo com diferentes teores de tanino e de umidade no colmo. III- Quebra de compostos nitrogenados

Foram estudadas silagens de quatro híbridos de sorgo, com diferentes teores de umidade no colmo combinados com teor alto ou baixo de tanino, em silos de laboratório feitos de tubos PVC, lacrados com fita crepe e dotados de uma válvula tipo Bunsen. Usaram-se 24 tratamentos com quatro repetições cada, sendo quatro híbridos (T1=colmo suculento e baixo tanino, T2=colmo seco e baixo tanino, T3=colmo seco e alto tanino, T4= colmo suculento e alto tanino) combinados com seis tempos para abertura do silo, sendo o primeiro tempo antes de ensilar (P1), seguido de 1, 7, 14, 28 e 56 dias de ensilagem. Determinaram-se os teores de matéria seca (MS), proteína bruta (PB), nitrogênio amoniacal (N-NH3) e tanino. Utilizou-se o teste de Tukey para comparação entre médias. Todos os híbridos produziram N-NH3 ao longo da fermentação. Os valores obtidos da fração N-amoniacal/N-total encontram-se abaixo dos valores citados na literatura. Silagens de híbridos com tanino alto apresentaram menores valores de N-amoniacal e maiores teores de matéria seca (P<0,05) que silagens de baixo tanino.

Silagem de sorgo de porte baixo, com diferentes teores de tanino e de umidade no colmo. IV- Influência dos taninos sobre a digestibilidade in vitro da matéria seca

Foram estudadas silagens de quatro híbridos de sorgo, com diferentes teores de umidade no colmo combinados com teor alto ou baixo de tanino, feitas em silos de tubos "PVC" em laboratório, lacrados com fita crepe e dotados de uma válvula tipo Bunsen. Usaram-se 24 tratamentos com 4 repetições cada, sendo 4 híbridos (T1=colmo suculento e baixo tanino, T2=colmo seco e baixo tanino, T3=colmo seco e alto tanino, T4= colmo suculento e alto tanino) combinados com 6 tempos para abertura do silo, sendo o primeiro tempos antes de ensilar (P1), seguido de 1, 7, 14, 28 e 56 dias de ensilagem. Os teores de matéria seca, tanino, componentes da parede celular e de digestibilidade in vitro da matéria seca (DIVMS) foram determinados nas silagens e nas forragens antes de ensilar (P1), após pré-secagem e moagem. Utilizou-se o teste de Tukey para comparação entre médias. A ensilagem provocou redução significativa nos teores de tanino, apesar de não ter essa diminuição resultado em aumento na digestibilidade in vitro da matéria seca. Ao contrário do que se esperava, a presença de taninos não reduziu a digestibilidade in vitro da matéria seca.