Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep

Subterranean Clover and Sulla as Valuable and Complementary Sources of Bioactive Compounds for Rainfed Mediterranean Farming Systems

Mediterranean pasture and forage legumes are important components of sustainable production systems. Subterranean clover and sulla represent key species having proven high agronomic value and traits for production and multiple services. Our research investigated the potential of the abovementioned species as a source of phenolic compounds and antioxidants for contributing to support their full exploitation in the fodder, animal welfare, and nutraceutical sectors. Antioxidant capacity, as well as the content of total phenolic compounds and individual phenolic compounds, was determined in subterranean clover and sulla shoots at the vegetative, flower bud, flowering, and seed ripening phenological stages. The antioxidant capacity and the phenolic content were affected significantly by harvest time. In subterranean clover, 10 individual phenolic compounds were detected, and isoflavones were the most abundant (3.19-18.27 mg·g^-1 DM). Eleven phenolic compounds were identified in sulla shoots, and chlorogenic acid (0.76-3.43 mg·g^-1 DM) and diosmin (3.64-4.94 mg·g^-1 DM) were the most represented compounds at the vegetative and flower bud stage. On the basis of our findings, a complementary utilization of both legume species is suggested; this might ensure the exploitation of all phenolic compounds in view of the potential benefits for animal production and health.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

Feeding Dairy Ewes with Fresh or Dehydrated Sulla (Sulla coronarium L.) Forage. 2. Effects on Cheese Enrichment in Bioactive Molecules

Simple Summary

Feeding ruminants with fresh sulla forage, containing polyphenols with antioxidant activity, seems to improve the performance of animals and the technological, nutritional and health properties of dairy products. However, the potential of sulla forage can be compromised by traditional methods, such as hay-making, to produce conserved forage; alternatively, dehydration could be an appropriate solution to preserve the content in bioactive components. This paper reports the effects of feeding dehydrated or fresh sulla forage on physico-chemical traits and health properties, due to antioxidant activity and fatty acid profile, of sheep cheese. An attempt was made also to identify cheese constituents that, being able to discriminate the ewes’ diet, may be proposed as biomarkers to trace cheese produced from animals fed with fresh forage. The results showed that the use of fresh or dehydrated sulla was able to enhance the health properties of cheeses, so dehydration can represent an opportunity to preserve the potential of fresh sulla forage. Moreover, α-linolenic acid and its ratio with linoleic acid showed the ability to discriminate cheese in relation to the animals’ feeding regime.

Abstract

Sulla is a tanniferous legume species largely used as fresh or preserved forage in the ruminants’ diets. Due to its content in polyphenols with antioxidant activity, especially condensed tannins (CT), fresh sulla forage (FSF), when eaten by ruminants, is able to enrich animal products with antioxidant molecules and polyunsaturated fatty acids (PUFA) that are beneficial for consumers’ health. Dehydration represents a valid alternative to haymaking to preserve these properties also in periods when FSF is unavailable. In this research, the effects of ewes’ diets based on sulla hay (SH), pelleted dehydrated sulla forage (DSF) or FSF were evaluated on cheese physico-chemical traits, including fatty acid (FA) profile, vitamins A and E, polyphenols, antioxidant capacity and oxidative stability. The individual daily milk from 10 first lambing (FL) and 10 third lambing (TL) Valle del Belìce ewes at about 60 days in milk, divided homogeneously into 5 groups fed different diets in a partial 5 × 2 Latin square design with 2 phases, and the bulk milk of farming ewes fed only on natural pasture, were used in 2 sessions of micro cheese-making to manufacture cheeses, sampled at 48 h of ripening. The experimental diets were: SHL = SH ad libitum; DSF2 = 2 kg/day DSF per head plus SH ad libitum; FSF2 = 2 kg/day FSF per head plus SH ad libitum; FSF4 = 4 kg/day FSF per head plus SH ad libitum; FSFL = FSF ad libitum. Concentrate was supplied at the amount of 0.8 or 1.2 kg/day per head for FL and TL, respectively. Cheese health properties greatly improved with FSFL diet, based on the exclusive use of fresh forage, that induced the increase in the content of molecules with antioxidant activity, as vitamin A, vitamin E and polyphenols, enhancing the oxidative stability, and the level of PUFA as rumenic acid (C18:2 c9t11) and α-linolenic acid (ALA, C18:3n-3). Cheeses from the DSF2 group showed levels of vitamin A, vitamin E and PUFA higher than SHL cheeses and comparable to those of FSF4 cheeses, whereas their ALA content was not different from that of FSFL cheeses. Evaluating those molecules affected by the level of fresh forage in the diet for their ability to trace the animals’ feeding regime, ALA and its ratio with linoleic acid (LA, C18:2n-6) (LA/ALA) exhibited an effective role as biomarker in discriminating cheese from animals fed fresh forage-based diets. The results showed how dehydrated sulla pellets, as an alternative to hay in periods of limited availability of fresh forage, can preserve the nutritional and health properties of dairy products with regards to their antioxidant capacity and FA profile.

Feeding Dairy Ewes with Fresh or Dehydrated Sulla (Sulla coronarium L.) Forage. 1. Effects on Feed Utilization, Milk Production, and Oxidative Status

Simple Summary

Sulla forage, containing condensed tannins, is renowned in the Mediterranean area for its excellent chemical composition and agronomic traits, the suitability for grazing or hay production, and favorable impact on ruminants’ productivity. Condensed tannins of sulla forage exert various positive effects, because they contribute to reducing methanogenesis in the rumen, protect dietary proteins from rumen degradation, limit the ruminal biohydrogenation of polyunsaturated fatty acids, and ensure animal health by anthelmintic action. Moreover, the antioxidant activity of condensed tannins may contribute to improving the antioxidant status of animals, as well as the oxidative stability and antioxidant properties of animal products, with important health benefits for human consumers. The conservation methods of sulla forage, such as dehydration and the hay-making process, can influence the content and bioavailability of condensed tannins. In this research, the performance of dairy ewes fed with pelleted dehydrated sulla forage, in terms of feed intake, digestibility, milk production, and oxidative status, were compared with those of ewes fed diets based on sulla hay and fresh sulla forage. The results confirmed the positive effects of sulla forage, also when fresh sulla forage is replaced with dehydrated forage. On this basis, the storage and use of sulla dehydrated pellets represent a valid opportunity to exploit the potential of sulla forage in periods of low availability of grazing sources.

Abstract

Feeding dairy ewes with fresh sulla forage (FSF), a legume species containing condensed tannins (CT), has been shown to increase feed intake, milk yield, and casein and enhances the oxidative status of animals. Dehydration of FSF could be an alternative to hay-making to preserve the nutritional properties. This research aimed to compare the responses of dairy ewes fed with diets based on sulla hay (SH), pelleted dehydrated sulla forage (DSF), or FSF in terms of efficiency of feed utilization, milk production, and the balance between oxidant (reactive oxygen metabolites (ROMs)) and antioxidant (biological antioxidant potential (BAP)) substances at the plasma level. Ten first-lambing (FL) and ten third-lambing (TL) ewes of the Valle del Belice breed at 60 days in milk were allocated into five homogeneous groups fed with different diets in a partial 5 × 2 Latin square design with two phases. The diets differed for the forage basis: SHL = SH ad libitum; DSF2 = 2 kg/day DSF per head plus SH ad libitum; FSF2 = 2 kg/day FSF per head plus SH ad libitum; FSF4 = 4 kg/day FSF per head plus SH ad libitum; FSFL = FSF ad libitum. A commercial concentrate was provided to FL (0.8 kg/day per head) and TL (1.2 kg/day per head) ewes. Dehydration induced slight variations in the content of protein and fiber, showed no loss of vitamin E and polyunsaturated fatty acids, and decreased the level of CT and polyphenols. The DSF2 diet resulted in a higher intake of dry matter, protein, and vitamin E compared to the other diets, whereas, compared to the FSFL diet, its intake was analogous for net energy and was lower in CT and polyphenols. The DSF2 diet was comparable to FSF4 and FSFL diets for milk yield, and to all diets for casein content and the clotting ability of milk. Ewes fed a DSF2 diet exhibited lowest values of ROMs and oxidative stress index (OSI = ROMs/BAP), indicating a better oxidative status, presumably due to the antioxidant protection exerted by the higher vitamin E intake and CT metabolites. These results confirmed the positive effects of FSF on milk production, especially due to CT intake, in improving the efficiency of dietary protein utilization, and showed how favorable effects also occur when FSF is replaced by DSF instead of SH.

Linking metabolites in eight bioactive forage species to their in vitro methane reduction potential across several cultivars and harvests

An in vitro Hohenheim gas test was conducted to analyze the fermentation end-products from 17 cultivars of eight polyphenol containing forage species. The polyphenol composition and proanthocyanidin (PA) structural features of all the cultivars were analyzed with UPLC-MS/MS in leaves of vegetative or generative plants. The samples were incubated with and without polyethylene glycol (PEG, a tannin-binding agent) to separate the tannin-effect on methane (CH_4, ml/200 mg DM) production from that of forage quality. Sulla and big trefoil, two particularly PA rich species, were found to have the highest CH₄ reduction potential of up to 47% when compared to the samples without PEG. However, concomitant reduction in gas production (GP, ml/200 mg DM) of up to 44% was also observed. An increase in both GP and CH₄ production under PEG treatments, confirms the role of tannins in CH₄ reduction. Moreover, PA structural features and concentration were found to be an important source of variation for CH₄ production from PA containing species. Despite having low polyphenol concentrations, chicory and plantain were found to reduce CH₄ production without reducing GP. Additionally, interspecies variability was found to be higher than intraspecies variability, and these results were consistent across growth stages, indicating the findings’ representativeness.

Involvement of Quebracho tannins in diet alters productive and reproductive efficiency of postpartum buffalo cows

This study was conducted to investigate the effects of 10 weeks supplementation of Quebracho tannins (QT; 0 [control], 100 [QT100] or 200 g/[cow·d] [QT200]) to 30 multiparous postpartum buffalo cows (10 cows per group) on milk yield and composition, blood metabolites and reproductive performance. Supplementation of QT100 had no significant effect on milk yield, whereas QT200 decreased (P < 0.05) this trait. Compared with the control group, both QT levels decreased (P < 0.05) fat-corrected milk (FCM) yield, but no significant effects were found on percentages of milk fat and protein. Contrariwise, yields of milk fat, lactose and milk protein were decreased (P < 0.05) when QT200 was supplemented. The solids nonfat (SNF) percentage and yield were decreased (P < 0.05) with QT100 supplementation. Moreover, QT tended to numerically reduce total number of ovarian follicles, number of small follicles, peripheral progesterone concentration and conception rate. Supplementation of QT200 numerically increased number of large follicles, mean diameter of large follicle, number and diameters of corpora lutea. The inclusion of QT200 shortened days open (DO) and decreased number of services per conception. Contrariwise, QT did not show significant effects on serum total protein, albumin, globulin, glucose, cholesterol and triglycerides concentrations. Supplementation of QT100 caused an increase (P < 0.05) of serum urea compared with that in control and QT200 groups. Generally, QT decreased (P < 0.05) serum creatinine concentration. Therefore, the supplementation of a commercial QT to early lactating Egyptian buffalo cows displayed negative consequences on their productive and reproductive performances.

Forage intake and weight gain of ewes is affected by roughage mixes during winter in northeastern China

We studied the effect of dietary roughage species and their combinations on forage intake and growth rate of ewes during winter in a pastoral-farming area of northeast China. Twenty-five Northeast crossbred ewes (fine-wool sheep × Small-tailed Han sheep) were randomly selected and divided into five groups (G1, G2, G3, G4 and G5). During a 30 day feeding trial, each group of ewes were offered the same basal diet (composed of 0.36 kg chopped maize stalk (10 mm), 0.14 kg corn meal, 0.05 kg soybean meal and 1.2 g NaCl) and one of the five supplementary roughage mixes, namely 100% Leymus chinensis hay (G1), 100% Vigna radiata stalk (G2), L. chinensis hay plus Suaeda glauca (G3), V. radiata stalk plus S. glauca (G4) and L. chinensis hay plus V. radiata stalk and S. glauca (G5). The results showed that roughage mixes had significant influences on daily roughage intake and daily weight gain of ewes. Ewes had greater daily roughage intake when supplemented with three species of roughage compared to the roughage with one species; however, there was no significant difference between G1 and G2, G3 and G4, or between G4 and G5. The average daily gain of ewes was also greater when they were supplemented with the roughage combination of L. chinensis, V. radiata stalk and S. glauca. No difference in average daily weight gain was observed between the G4 and G5 treatments (P > 0.05). The lowest average daily weight gain was observed when the ewes were supplemented with V. radiata stalk alone (G2) (P < 0.05). The results indicated that supplying ewes with various roughages simultaneously in winter could improve their forage intake and average daily weight gain compared to offering the ewes only one type of dietary roughage. Further, feeding roughage supplements containing a diverse mix of roughage species represents one method for increasing roughage utilization in livestock production during winter in the pastoral-farming areas of northeastern China.

Effects of ewes grazing sulla or ryegrass pasture for different daily durations on forage intake, milk production and fatty acid composition of cheese

Sulla (Sulla coronarium L.) forage is valued for its positive impact on ruminant production, in part due to its moderate content of condensed tannin (CT). The duration of daily grazing is a factor affecting the feed intake and milk production of ewes. In this study, the effects of grazing sulla pasture compared with annual ryegrass, and the extension of grazing from 8 to 22 h/day, were evaluated with regard to ewe forage intake and milk production, as well as the physicochemical properties and fatty acid (FA) composition of cheese. During 42 days in the spring, 28 ewes of the Comisana breed were divided into four groups (S8, S22, R8 and R22) that grazed sulla (S) or ryegrass (R) for 8 (0800 to 1600 h) or 22 h/day, and received no feeding supplement. In six cheese-making sessions, cheeses were manufactured from the 48 h bulk milk of each group. Compared with ewes grazing ryegrass, those grazing sulla had higher dry matter (DM) intake, intake rate and milk yield, and produced milk that was lower in fat and higher in casein. Ewes grazing for 22 h spent more time eating, which reduced the intake rate, increased DM and nutrient intake and milk yield, and reduced milk fat. Due to the ability of CT to inhibit the complete ruminal biohydrogenation of polyunsaturated fatty acids (PUFA), the FA composition of sulla cheese was more beneficial for consumer health compared with ryegrass cheese, having lower levels of saturated fatty acids and higher levels of PUFA and n-3 FA. The FA profile of S8 cheese was better than that of S22 cheese, as it was higher in branched-chain FA, monounsaturated FA, PUFA, rumenic acid (c9,t11-C18:2), and had a greater health-promoting index. The effect of short grazing time on sulla was attributed to major inhibition of PUFA biohydrogenating ruminal bacteria, presumably stimulated by the higher accumulation of sulla CT in the rumen, which is related to a higher intake rate over a shorter eating time. Thus, grazing sulla improved the performance of ewes, thereby increasing, especially with short grazing time, the nutritional properties of cheese fat.

Effects of Sulla forage (Sulla coronarium L.) on the oxidative status and milk polyphenol content in goats

Twelve milking Girgentana goats were allocated into 3 groups and fed 3 diets ad libitum in a 3×3 Latin square design with 3 periods. The diets were Sulla fresh forage ad libitum (SUL), Sulla fresh forage ad libitum and 800g/d of barley meal (SULB), and mixed hay ad libitum and 800g/d of barley meal (HB). Changes were observed in total polyphenol intake, plasma oxidative status, plasma polyphenol content, metabolic status, milk polyphenol content, and total antioxidant capacity. The fresh forage diets (SUL and SULB) increased dry matter, total polyphenol, nontannic polyphenol and tannin intakes, and the milk total protein, casein, milk total polyphenols, and milk free polyphenols compared with the HB diet. The intake of condensed tannins was higher in the SUL than in the HB group, and an intermediate value was recorded for the SULB group. Plasma from the SUL- and SULB-fed goats exhibited greater total antioxidant capacity and greater total polyphenol and free polyphenol levels compared with the plasma from the HB group. Positive correlations between plasma total antioxidant capacity and condensed tannins intake (r=0.43), plasma total polyphenol and total polyphenol intake (r=0.61), and plasma free polyphenol and milk total polyphenols (r=0.38) were observed. The correlation between milk free polyphenols and whey total antioxidant capacity (r=0.42) highlights the role of free polyphenols in the determination of the antioxidant activity of milk. These results indicate that Sulla fresh forage exerts an antioxidant activity due to its secondary compounds that provide additional antioxidant value and that Sulla forage appears to be a promising strategy for improving product quality.

Grape marc reduces methane emissions when fed to dairy cows

Grape marc (the skins, seeds, stalk, and stems remaining after grapes have been pressed to make wine) is currently a by-product used as a feed supplement by the dairy and beef industries. Grape marc contains condensed tannins and has high concentrations of crude fat; both these substances can reduce enteric methane (CH4) production when fed to ruminants. This experiment examined the effects of dietary supplementation with either dried, pelleted grape marc or ensiled grape marc on yield and composition of milk, enteric CH4 emissions, and ruminal microbiota in dairy cows. Thirty-two Holstein dairy cows in late lactation were offered 1 of 3 diets: a control (CON) diet; a diet containing dried, pelleted grape marc (DGM); and a diet containing ensiled grape marc (EGM). The diet offered to cows in the CON group contained 14.0kg of alfalfa hay dry matter (DM)/d and 4.3kg of concentrate mix DM/d. Diets offered to cows in the DGM and EGM groups contained 9.0kg of alfalfa hay DM/d, 4.3kg of concentrate mix DM/d, and 5.0kg of dried or ensiled grape marc DM/d, respectively. These diets were offered individually to cows for 18d. Individual cow feed intake and milk yield were measured daily and milk composition measured on 4d/wk. Individual cow CH4 emissions were measured by the SF6 tracer technique on 2d at the end of the experiment. Ruminal bacterial, archaeal, fungal, and protozoan communities were quantified on the last day of the experiment. Cows offered the CON, DGM, and EGM diets, ate 95, 98, and 96%, respectively, of the DM offered. The mean milk yield of cows fed the EGM diet was 12.8kg/cow per day and was less than that of cows fed either the CON diet (14.6kg/cow per day) or the DGM diet (15.4kg/cow per day). Feeding DGM and EGM diets was associated with decreased milk fat yields, lower concentrations of saturated fatty acids, and enhanced concentrations of mono- and polyunsaturated fatty acids, in particular cis-9,trans-11 linoleic acid. The mean CH4 emissions were 470, 375, and 389g of CH4/cow per day for cows fed the CON, DGM, and EGM diets, respectively. Methane yields were 26.1, 20.2, and 21.5g of CH4/kg of DMI for cows fed the CON, DGM, and EGM diets, respectively. The ruminal bacterial and archaeal communities were altered by dietary supplementation with grape marc, but ruminal fungal and protozoan communities were not. Decreases of approximately 20% in CH4 emissions and CH4 yield indicate that feeding DGM and EGM could play a role in CH4 abatement.

Condensed tannin accumulation and nitrogen fixation potential of Onobrychis viciifolia Scop. grown in a Mediterranean environment

BACKGROUND

Sainfoin (Onobrychis viciifolia Scop.) is a forage legume found in temperate areas but is less widespread in Mediterranean environments. Compared with other perennial legumes, it has the advantage of containing condensed tannins (CT) that can be important for their implications on ruminant nutrition and health. Data on nitrogen (N) fixation by sainfoin in the literature originate from very different environments and only a few field data are available, so it is important to improve knowledge on the N fixation potential of this species, particularly under a Mediterranean climate. Here the accumulation pattern of polyphenolic compounds (total, non-tannic polyphenols and CT) and the N fixation potential of sainfoin were studied in order to contribute to its valorisation for sustainable farming management in Mediterranean environments.

RESULTS

CT concentrations were always in the range considered beneficial for animals, not exceeding 50 g delphinidin equivalent kg⁻¹ dry matter (DM). The regression of aerial fixed N on aerial DM showed a relationship of 22 kg fixed N t⁻¹ aerial DM in a Mediterranean environment.

CONCLUSION

A wider exploitation of sainfoin is suggested for production under rain-fed conditions, thus enlarging the limited set of available perennial legumes suitable for Mediterranean environments.

Effects of dietary cottonseed oil and tannin supplements on protein and fatty acid composition of bovine milk

This experiment was conducted to determine the effects of diets supplemented with cottonseed oil,Acacia mearnsii-condensed tannin extract, and a combination of both on composition of bovine milk. Treatment diets included addition of cottonseed oil (800 g/d; CSO), condensed tannin fromAcacia mearnsii(400 g/d; TAN) or a combination of cottonseed oil (800 g/d) and condensed tannin (400 g/d; CPT) with a diet consisting of 6·0 kg dry matter (DM) of concentrates and alfalfa hay ad libitum, which also served as the control diet (CON). Relative to the CON diet, feeding CSO and CPT diets had a minor impact on feed intake and yield of lactose in milk. These diets increased yields of milk and protein in milk. In contrast to the TAN diet, the CSO and CPT diets significantly decreased milk fat concentration and altered milk fatty acid composition by decreasing the proportion of saturated fatty acids but increasing proportions of monounsaturated and polyunsaturated fatty acids. The CPT diet had a similar effect to the CSO diet in modifying fatty acid profile. Overall, reduction in milk fat concentration and changes in milk fatty acid profile were probably due to supplementation of linoleic acid-rich cottonseed oil. The TAN diet had no effect on feed intake, milk yield and milk protein concentration. However, a reduction in the yields of protein and lactose occurred when cows were fed this diet. Supplemented tannin had no significant effect on fat concentration and changes in fatty acid profile in milk. All supplemented diets did not affect protein concentration or composition, nitrogen concentration, or casein to total protein ratio of the resulting milk.

Influence of fresh forage-based diets and αs₁-casein (CSN1S1) genotype on nutrient intake and productive, metabolic, and hormonal responses in milking goats

Polymorphism at the αS1-casein locus (CSN1S1) in goats influences several milk production traits. Milk from goats carrying strong alleles, which are associated with high αS1-casein (αS1-CN) synthesis, has higher fat and casein contents, longer coagulation time and higher curd firmness than milk from goats with weak alleles linked to low αS1-CN content. Nutrition also affects these milk properties; therefore, it is important to better understand the interaction between dietary characteristics and the CSN1S1 genotype in goats. This study aimed to investigate the effect of fresh forage based diet or energy supplement on feeding behavior, milk production, and metabolic and hormonal parameters of Girgentana goats with different genotypes at CSN1S1 loci. From a group of goats genotyped by PCR at the DNA level, 12 were selected because they had the same genotype for αS2-CN, β-CN, and κ-CN but a different genotype for αS1-CN: 6 were homozygous for strong alleles at the CSN1S1 loci (AA) and 6 were heterozygous for a weak allele (AF). Goats of each genotype were allocated to 3 subgroups and fed 3 diets ad libitum in a 3×3 Latin square design. The diets were sulla (Hedysarum coronarium L.) fresh forage, sulla fresh forage plus 800 g/d of barley meal (SFB), and mixed hay plus 800 g/d of barley meal (MHB). Diet had a stronger effect than CSN1S1 genotype. The SFB diet led to the highest energy intake, dry matter (DM) digestibility, and milk yield. The fresh forage diets (SFF and SFB) increased DM and crude protein (CP) intake, CP digestibility, and milk CN compared with the MHB diet. The diets supplemented with energy (SFB, MHB) reduced milk fat and urea, improved CP utilization for casein synthesis, and limited body fat mobilization, in accordance with a lower level of nonesterified fatty acids and higher levels of glucose and IGF-1. With regard to CSN1S1 genotype, AA goats showed higher CP digestibility and lower free thyroxine hormone and cholesterol levels than AF goats. Significant diet × genotype interactions indicated how AA goats, compared with AF goats, showed higher DM digestibility and milk yield when fed the SFB diet, which had more energy. A reduction in free triiodothyronine hormone occurred in AF goats fed the MHB diet, whereas no differences were observed in AA goats. These results demonstrate how goats with a higher capacity for αS1-CN synthesis exhibit more efficient energy and protein utilization, evident at the digestive level, and better productive responses to high-nutrition diets.

Milk yield and quality in Guernsey cows fed cottonseed cake-based diets partially substituted with baobab (Adansonia digitata L.) seed cake

The objective of this study was to determine the effects of partially substituting cottonseed cake with graded levels of baobab (Adansonia digitata L.) seed cake (BSC) on milk yield and quality in Guernsey cows. Sixteen cows in mid-lactation and in their third parity were allocated to diets containing 0% (control), 5%, 10%, and 15% BSC in a completely randomized design. Each cow was given a daily feed ration of 6 kg and a basal diet of soya bean stover ad libitum. There were no differences in daily feed intake (P > 0.05), but basal intake differed among all treatment groups with cows on the control diet having the highest intake (30 ± 0.34 kg/day). Mean daily milk yield differed (P < 0.05) among all treatment groups. However, the control had higher milk yield of 12.1 ± 0.73 kg/day, and the 15% BSC had the least yield of 7.46 ± 0.73 kg/day. Cows on the control diet had higher milk butterfat content (6.12%; P < 0.05) than those on the BSC-based diets. Protein content differed (P < 0.05) across all treatment groups with cows on 15% BSC producing the highest protein content (3.43%) while the control had the least (2.6%). The concentration of milk total solids for cows fed on 15% BSC was higher (P < 0.05) than that from cows on other diets. Lactose content was not affected by the diets (P > 0.05). These results indicate that BSC can substitute soya bean cake in dairy diets, but milk production and butterfat content are compromised.

The dynamics of phenolic concentration in some pasture species and implications for animal husbandry

BACKGROUND

Although secondary metabolites have often been studied considering their primary role as plant-defensive and their effect on consumers detrimental, their effects are usually dose-dependent, so it is important to consider their content at all phenological phases and in different plant organs. In this study the content of total phenolics (TotP), non-tannic phenolics (NTP) and proanthocyanidins (PA) was determined in natural populations of pasture species at defined phenological phases and in different plant organs and also in pathogen-infected plants.

RESULTS

Variation in TotP, NTP and PA content was observed in all species, phenological phases and plant organs. Leaf blades were the organs with the highest content in all species. The content of all examined compounds increased in infected leaves, reaching the maximum when 20% of plant tissues were attacked and decreasing at higher infection levels.

CONCLUSION

Delphinidin was found as an appropriate standard related to the PA structure of each plant species. PA concentrations were always in the range considered beneficial for animals, not exceeding 60 g delphinidin equivalent kg(-1) dry matter. The Folin-Ciocalteu and butanol/HCl/Fe(3+) assays remain the most practical methods for screening large numbers of different plant species for TotP and PA.