Digesta retention time and recovery rates of ants and termites in Chinese pangolins (Manis pentadactyla)

Pangolins are myrmecophagous mammals whose biology and ecology remain poorly studied. Termite mandibles and ant head capsules are the two primary remains found in pangolin feces. Determining the retention time of insect cuticles is important for understanding the digestive physiology of pangolins, while determining the recovery rate of termites and ants in feces is required to estimate the number of these prey items that are consumed by pangolins. In this study, the authors conducted feeding trials with captive Chinese pangolins (Manis pentadactyla). Sixty grams of the fungus-growing termite Odontotermes formosanus (18,816 individuals) and 15–20 g of the yellow crazy ant Anoplolepis gracilipes (14,400–19,200 individuals) were fed to each pangolin. After feeding, pangolin feces were collected daily for 1 week. The authors also assessed the accuracy of using chromium (III) oxide powder (Cr₂O₃) as a proxy for determining gut passage time, as has been done in previous studies. The results showed that remaining termite mandibles and ant head capsules in feces peaked at 66 and 90 hr after feeding and their recovery rates were 0.35 ± 0.10 and 0.65 ± 0.04, respectively. In both feeding trials, the retention time of Cr₂O₃ was much shorter than that of the termite mandibles and ant head capsules, indicating that Cr₂O₃ is not an appropriate indicator for estimating food retention time of myrmecophagous animals. Our results revealed that the ant head capsules were preserved better in feces compared with the termite mandibles, suggesting that termites may be considerably underestimated in the feces of wild pangolins.     

Isolation and characterization of microsatellite markers in pangolins (Mammalia,Pholidota, Manis spp.)

Thirty‐four polymorphic dinucleotide microsatellite loci were developed in the Malayan pangolin Manis javanica. Of the 34 markers, 32 and 18 were also amplified, respectively, in the Chinese pangolin (Manis pentadactyla) and the African tree pangolin (Manis tricuspis). Analysis of 24 Malayan, 12 Chinese and 2 African tree pangolins showed high levels of variability (heterozygosity ranging from 0.321 to 0.708). These are the first available microsatellite markers in Pholidota and will be an invaluable tool for evolutionary and conservation genetic studies in pangolins.     

Comparative study of gut microbiota from captive and confiscated-rescued wild pangolins

Pangolins are among the most critically endangered animals due to widespread poaching and worldwide trafficking. Captive breeding is considered to be one way to protect them and increase the sizes of their populations. However, comparative studies of captive and wild pangolins in the context of gut microbiota are rare. Here, the gut microbiome of captive and confiscated-rescued wild pangolins is compared, and the effects of different periods of captivity and captivity with and without antibiotic treatment are considered. We show that different diets and periods of captivity, as well as the application of antibiotic therapy, can alter gut community composition and abundance in pangolins. Compared to wild pangolins, captive pangolins have an increased capacity for chitin and cellulose/hemicellulose degradation, fatty acid metabolism, and short-chain fatty acid synthesis, but a reduced ability to metabolize exogenous substances. In addition to increasing the ability of the gut microbiota to metabolize nutrients in captivity, captive breeding imposes some risks for survival by resulting in a greater abundance of antibiotic resistance genes and virulence factors in captive pangolins than in wild pangolins. Our study is important for the development of guidelines for pangolin conservation, including health assessment, disease prevention, and rehabilitation of wild pangolin populations.     

Influence of different fibre sources on digestibility and nitrogen and energy balances in growing pigs

Abstract

The present study was undertaken to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, constituting 15% of diets for growing pigs, influenced daily body gain, feed conversion, apparent faecal digestibility and nitrogen and energy balances. Eight castrated crossbreed pigs (30 – 80 kg live weight) were used in a replicated 4 × 4 Latin-square design with one control diet and three fibre containing diets. Daily body weight gain and feed conversion were not affected by the dietary treatments. The apparent faecal digestibility of organic matter (OM) and energy were significantly lower for the fibre diets (OM: 0.81 – 0.85; energy: 0.78 – 0.83) compared to the control diet (OM: 0.88; energy: 0.86). The apparent faecal digestibility of crude protein (CP) was lower for the fibre diets (0.71 – 0.78) compared to the control diet (0.83), although it was only significantly lower for the sugar beet pulp and pectin residue diets. The pectin residue diet, which contained the highest amount of dietary fibre, lignin and insoluble non-starch polysaccharides, had the lowest digestibility of OM, CP and energy. There was a tendency (p = 0.07) for a diet effect on retained nitrogen in proportion to digested nitrogen, where the sugar beet pulp and pectin residue diets had numerically the highest values. Heat production and retained energy in proportion to metabolizable energy intake were not affected by fibre inclusion. It was concluded that the inclusion of sugar beet pulp, soya bean hulls and pectin residue in diets for growing pigs decreased the apparent faecal digestibility and in the diets with sugar beet pulp and pectin residue higher utilization of digested nitrogen for retention compensated for the lower amount of digested nitrogen.     

Reproductive behavior of the captive Sunda pangolin (Manis javanica Desmarest, 1822)

Understanding reproductive behavior is important for the conservation of endangered species, but research on the reproductive behavior of Sunda pangolins (Manis javanica Desmarest, 1822) is still very scarce. In this study, we used focal animal sampling and all-occurrence recording by an infrared monitor to observe the behaviors of two Sunda pangolins during a 5-day breeding period at the Pangolin Research Base for Artificial Rescue and Conservation Breeding of South China Normal University (PRB-SCNU). The behavioral characteristics and breeding strategies were analyzed, and the results were discussed together with information on other captive Sunda pangolin pairs at PRB-SCNU. The results found that there was no obvious estrus behavior in the captive female, while the male could exhibit sexual excitement and courtship behavior after a brief introduction period. Repeated copulation continued over many days after the female accepted the courtship. The average duration of copulatory behavior was 248.9 ± 148.7 s (n = 25), and all copulation occurred between 20:00 and 08:00 hr in the natural day–night photoperiod. The mating position of Sunda pangolins was lateral–ventral and was classified as the ninth or eleventh pattern under both Dewsbury's and Dixson's classification systems. This study can provide scientific guidance for the captive breeding and management of Sunda pangolins and other pangolin species, which is of great significance for ex situ conservation tactics.     

Effect of high fibre diets formulated with different fibrous ingredients on performance,nutrient digestibility and faecal microbiota of weaned piglets

The aim of the experiment on 180 weaned piglets (8.9 kg body weight) was to investigate the influence of high fibre diets formulated with different fibrous ingredients on performance, nutrient digestibility, diarrhoea incidence and numbers of faecal microbiota. The dietary treatments included a Control diet and five high fibre diets formulated with different fibre sources including wheat bran, soybean hulls, naked oat hulls, palm kernel expeller and bamboo fibre. The high fibre diets averaged 14.6% neutral detergent fibre with different non-starch polysaccharides (NSP) components and were fed ad libitum for 28 d. Faecal samples were collected during the last 3 d of the experiment and the apparent total tract digestibility of nutrients and fibre components were determined. Pigs fed the Control and wheat bran diets had a higher (p ≤ 0.05) average daily gain (ADG) than pigs fed the palm kernel expeller and bamboo meal diets. The reduced ADG for pigs appeared to be related to reductions in the digestibility of gross energy and dry matter, respectively. The feed-to-gain ratio was significantly higher (p ≤ 0.05) for pigs fed the fibre diets. The digestibility of NSP components was different among the treatments. The diarrhoea incidence was not affected by treatments. The abundance of faecal bifidobacteria was significantly higher (p ≤ 0.05) for pigs fed the wheat bran diet than for pigs fed the bamboo meal diet. It was concluded that the diets formulated with different fibre sources when fed to weaned piglets have different effects on pig performance, nutrient digestibility and numbers of faecal microbiota. The wheat bran diet rich in arabinoxylans enabled a better performance than the other tested diets with fibre addition.     

Effects of fibre on digestibility and passage time in callithricidae

The effects of fibre in a pelleted diet on food intake, digestibility of crude fibre, dry matter and energy, on passage time and consistency of faeces were studied in 2 species of Callithricidae, Callithrix jacchus and Saguinus fuscicollis. Coarse cellulose, microcellulose, wheat bran and shrimp meal (chitin = crude fibre) were tested in diets containing 2,4 and 6% total crude fibre, respectively. Digestibility and passage time were determined by inclusion of 0.5% Cr2O3 in the diet. Both celluloses had little influence on the digestibility of energy and dry matter. Digestibility of crude fibre was very low. Wheat bran led to evident depression of energy and dry matter digestibility. High digestibility of crude fibre occurred at the higher levels of inclusion in the diet. Shrimp meal was highly digested with little influence on digestibility of energy and dry matter, indicating considerable degradation of chitin. Wheat bran showed a marked effect, while microcellulose had no effect on passage time, consistency and volume of faeces.     

Harvesting, rumination, digestion, and passage of fruit and leaf diets by a small ruminant, the blue duiker

Because small ruminants (<15 kg) have a high ratio of metabolic rate to fermentation capacity, they are expected to select and require low-fiber, nutrient-dense concentrate diets. However, recent studies suggest that small ruminants may not be as limited in their digestive capacity as previously thought. In this study, we examined harvesting, rumination, digestion, and passage of three diets (domestic figs Ficus carica, fresh alfalfa Medicago sativa, and Pacific willow leaves Salix lasiandra) ranging from 10 to 50% neutral detergent fiber content (NDF) in captive blue duikers (Cephalophus monticola, 4 kg). Harvesting and rumination rates were obtained by observing and videotaping animals on each diet, and digestibility and intake were determined by conducting total collection digestion trials. We estimated mean retention time of liquid and particulate digesta by administering Co-EDTA and forages labelled with YbNO₃ in a pulse dose and monitoring fecal output over 4 days. Duikers harvested and ruminated the fig diet faster than the alfalfa and willow diets. Likewise, they achieved higher dry matter, energy, NDF, and protein digestibility when eating figs, yet achieved a higher daily digestible energy intake on the fresh willow and alfalfa than on the figs by eating proportionately more of these forages. Duikers maintained a positive nitrogen balance on all diets, including figs, which contained only 6.3% crude protein. Mean retention time of cell wall in the duikers’ digestive tract declined with increasing NDF and cellulose content of the diet. Digestibility coefficients and mean retention times of these small ruminants were virtually equivalent to those measured for ruminants two orders of magnitude larger, suggesting that they are well adapted for a mixed diet. Received: 10 August 1999 / Accepted: 16 November 1999     

Conservation genomics reveals possible illegal trade routes and admixture across pangolin lineages in Southeast Asia

The use of genome-wide genetic markers is an emerging approach for informing evidence-based management decisions for highly threatened species. Pangolins are the most heavily trafficked mammals across illegal wildlife trade globally, but critically endangered Sunda pangolins (Manis javanica) have not been widely studied in insular Southeast Asia. We used?>?12,000 single nucleotide polymorphic markers (SNPs) to assign pangolin seizures from illegal trade of unknown origin to possible geographic sources via genetic clustering with pangolins of known origin. Our SNPs reveal three previously unrecognized genetic lineages of Sunda pangolins, possibly from Borneo, Java and Singapore/Sumatra. The seizure assignments suggest the majority of pangolins were traded from Borneo to Java. Using mitochondrial markers did not provide the same resolution of pangolin lineages, and to explore if admixture might explain these differences, we applied sophisticated tests of introgression using?>?2000 SNPs to investigate secondary gene flow between each of the three Sunda pangolin lineages. It is possible the admixture which we discovered is due to human-mediated movements of pangolins. Our findings impact a range of conservation actions, including tracing patterns of trade, repatriation of rescue animals, and conservation breeding. In order to conserve genetic diversity, we suggest that, pending further research, each pangolin lineage should as a precaution be protected and managed as an evolutionarily distinct conservation unit.     

Effects of Acomastylis rossii tannins on a mammalian herbivore,the North American pika,Ochotona princeps

 I investigated the effects of tannin consumption, using plant tannins naturally occurring in the diet, on a herbivorous mammal, the North American pika, Ochotona princeps. The objectives were to determine if a high-tannin diet influenced protein and dry matter apparent digestibility, fiber digestibility and production of detoxification by-products. Additionally, I examined the possibility that pikas produce salivary tannin-binding proteins, a potential mechanism for avoiding detrimental effects of tannins. My results demonstrate that although pikas constitutively produce salivary tannin-binding proteins, animals consuming a high-tannin diet of Acomastylis rossii exhibited lower dry matter, protein and fiber digestion and excreted higher concentrations of detoxification by-products. Thus, A. rossii tannins are potential toxins as well as digestibility reducers. I propose a hypothesis coupling detoxification to reduced fiber digestion that is applicable to pikas as well as other mammalian herbivores consuming phenolic-rich diets. Received: 31 July 1995 / Accepted: 9 July 1996     

Influence of different fibre sources on digestibility and nitrogen and energy balances in growing pigs

The present study was undertaken to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, constituting 15% of diets for growing pigs, influenced daily body gain, feed conversion, apparent faecal digestibility and nitrogen and energy balances. Eight castrated crossbreed pigs (30-80 kg live weight) were used in a replicated 4 x 4 Latin-square design with one control diet and three fibre containing diets. Daily body weight gain and feed conversion were not affected by the dietary treatments. The apparent faecal digestibility of organic matter (OM) and energy were significantly lower for the fibre diets (OM: 0.81-0.85; energy: 0.78-0.83) compared to the control diet (OM: 0.88; energy: 0.86). The apparent faecal digestibility of crude protein (CP) was lower for the fibre diets (0.71-0.78) compared to the control diet (0.83), although it was only significantly lower for the sugar beet pulp and pectin residue diets. The pectin residue diet, which contained the highest amount of dietary fibre, lignin and insoluble non-starch polysaccharides, had the lowest digestibility of OM, CP and energy. There was a tendency (p = 0.07) for a diet effect on retained nitrogen in proportion to digested nitrogen, where the sugar beet pulp and pectin residue diets had numerically the highest values. Heat production and retained energy in proportion to metabolizable energy intake were not affected by fibre inclusion. It was concluded that the inclusion of sugar beet pulp, soya bean hulls and pectin residue in diets for growing pigs decreased the apparent faecal digestibility and in the diets with sugar beet pulp and pectin residue higher utilization of digested nitrogen for retention compensated for the lower amount of digested nitrogen.     

More efficient mastication allows increasing intake without compromising digestibility or necessitating a larger gut: Comparative feeding trials in banteng (Bos javanicus) and pygmy hippopotamus (Hexaprotodon liberiensis)

The digestion of plant material in mammalian herbivores basically depends on the chemical and structural composition of the diet, the mean particle size to which the forage is processed, and the ingesta retention time. These different factors can be influenced by the animal, and they can presumably compensate for each other. The pygmy hippopotamus, a non-ruminating foregut fermenter, has longer mean retention times than ruminants; however hippos do not achieve higher (fibre) digestibilities on comparable diets, which could be due to ineffective mastication. We performed feeding trials with six pygmy hippos (Hexaprotodon liberiensis) and six banteng cattle (Bos javanicus) on a grass diet. As predicted, both species achieved similar dry matter, organic matter, crude protein and gross energy digestibilities. However, neutral and acid detergent fibre digestibility was lower in pygmy hippos. Apparently, in these species, fibre digestibility was more influenced by particle size, which was larger in pygmy hippos compared to banteng, than by retention time. In spite of their higher relative food intake, the banteng in this study did not have greater relative gut fills than the hippos. Ruminants traditionally appear intake-limited when compared to equids, because feed particles above a certain size cannot leave the rumen. But when compared to nonruminating foregut fermenters, rumination seems to free foregut fermenters from an intrinsic food intake limitation. The higher energy intakes and metabolic rates in wild cattle compared to hippos could have life-history consequences, such as a higher relative reproductive rate.     

Effects of konjac flour inclusion in gestation diets on the nutrient digestibility,lactation feed intake and reproductive performance of sows

This study was conducted to investigate the effects of konjac flour (KF) inclusion in gestation diets of sows on nutrients digestibility, lactation feed intake, reproductive performance of sows and preweaning performance of piglets. Two isoenergetic and isonitrogenous gestation diets were formulated: a control diet and a 2.1% KF-supplemented diet (KF diet). Both diets had the same NDF and insoluble fiber (ISF) levels, but the KF diet had higher soluble fiber (SF) level. The day after breeding, 96 multiparous sows were assigned to the two dietary treatments. Restrict-fed during gestation, in contrast, all sows were offered the same lactation diet ad libitum. Response criteria included sow BW, backfat depth, lactation feed intake, weaning-to-estrus interval, litter size and piglet’s weight at parturition and day 21 of lactation. On day 60 of gestation, 20 sows were used to measure nutrient digestibility. Results showed that the digestibility of dry matter, gross energy, crude fiber and ADF were not affected by the dietary treatments. The inclusion of KF in gestation diets increased NDF digestibility (P<0.05) and tended to increase the digestibility of CP (P=0.05) compared with the control diet group. In addition, dietary treatment during gestation did not affect litter size, BW and backfat gain during gestation, lactation weight, backfat loss or weaning-to-estrus interval of sows. However, sows fed the KF diet consumed more (P<0.05) lactation diet per day than sows in the control group. Accordingly, sows fed the KF diet showed greater average piglet weights on day 21 of lactation (P=0.09), and the litter weight of sows fed the KF diet on day 21 of lactation increased by 3.95 kg compared with sows fed the control diet (not significant). In conclusion, the inclusion of KF in gestation diets increased lactation feed intake of sows and tended to improve litter performance.     

Limits to food intake and fiber utilization in the prairie vole,Microtus ochrogaster: effects of food quality and energy need

We fed prairie voles (Microtus ochrogaster) rat chow diluted with variable amounts of -cellulose to determine 1) how much fiber the voles could tolerate in their diet; 2) changes in food intake and digestibility of dry matter and of fiber; 3) the extent to which voles utilized fiber as an energy source; and 4) whether any of these variables differed between groups of animals maintained at 5 or 22°C. Fiber content of the diets ranged from 20 to 84%. Animals held at 5°C maintained body mass through a diet containing 69% fiber, while animals held at 22°C maintained body mass through the 84% fiber diet. Dry matter intake increased with fiber level from 9.3 to 15.0 g·day^-1 for animals at 5°C and from 5.6 to 14.0 g·day^-1 for animals at 22°C; intake on the highest fiber diet eaten by either group was not different. Dry matter digestibility decreased significantly as the fiber in the diets increased, but was not affected by temperature treatments. Digestible dry matter intake for each group remained constant regardless of diet quality, but on each diet digestible dry matter intake for animals at 5°C was significantly higher than that of the animals held at 22°C. Digestibility of the fiber portion of the experimental diets remained constant as food quality decreased, so the percent of daily energy need met by fiber utilization increased with higher food intake. On the lowest quality diet each group tolerated, fiber digestion provided approximately 42 and 68% of the energy needs of voles at 5 and 22°C, respectively.Abbreviations BM body mass - BMR basal metabolic rate - DE digestible energy - DM dry matter - DMD dry matter digestibility - DDMI digestible dry matter intake - MR metabolic rate - NDF neutral detergent fiber (=cell walls) - NDS neutral detergent solubles (=cell solubles) - SEM standard error of mean - T _a ambient temperature     

Performance,feeding behaviour and microbial diversity in weaned piglets fed liquid diets based on water or wet wheat-distillers grain

Performance, nutrient digestibility, feeding behaviour, diarrhoea frequency and faecal microbial diversity was studied in weaned piglets allotted to dry feed (diet A), liquid feed with water (diet B) or liquid feed with wet wheat-distillers grain (diet C). There were no differences in digestibility of organic matter and energy, and the performance was similar between piglets fed liquid diets. Piglets fed diet A spent more time on eating/drinking compared with piglets fed liquid diets. The frequency of diarrhoea decreased (p?<?0.05) from from diet A (11 out of 16) to diet B (6 out of 16) and further to diet C (1 out 16). The type of diet did not affect the diversity of coliform bacteria or lactobacilli, but the composition of the Lactobacillus flora was changed. The lower diarrhoea frequency when feeding diet C may be due to a prophylactic effect induced by the inclusion of wet wheat-distillers grain in the diet.     

The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis

The present study was undertaken in order to effect a comprehensive phylogenetic analysis of the order Pholidota, examining seven of the eight currently recognized extant species (absent is Manis culionensis, formerly recognized as a subspecies of Manis javanica) and nearly all the well-known fossil taxa, and employing a wide range of osteological characters from the entire skeleton. In addition, the relationship of pangolins to several putative early Tertiary relatives, including palaeanodonts and the enigmatic “edentate” Eurotamandua joresi, were investigated. The goal of the study was to improve understanding of the systematics and the biogeographic and evolutionary history of the pangolins. A computer-based cladistic analysis of phylogenetic relationships among seven extant species of pangolins, five extinct pangolin species (including all but one of the well-preserved taxa), as well as Eurotamandua and two genera of metacheiromyid palaeanodonts, Palaeanodon and Metacheiromys, was performed based upon 395 osteological characteristics of the skull and postcranial skeleton. Characters were polarized via comparison to the following successive outgroups: the basal feliform carnivoran Nandinia binotata and the hedgehog Erinaceus sp., a eulipotyphlan laursiatherian placental. A revised classification is presented based on the results of the analysis. The results support the monophyly of Pholidota and Palaeanodonta by providing new anatomical characters that can serve to diagnose a pangolin/palaeanodont clade, termed here Pholidotamorpha. Pholidota is defined so as to include all living and fossil pangolins, including all three taxa of middle Eocene “edentates” from the Messel fauna of Germany, among them Eurotamandua joresi. The results do not support the monophyly of the remaining two Messel “edentates” originally placed in the same genus Eomanis, which is restricted to the type species Eomanis waldi. Euromanis, new genus, is named with Eomanis krebsi Storch and Martin, 1994, as the type species, to form a new combination Euromanis krebsi (Storch and Martin, 1994). The analysis strongly supports the monophyly of a crown clade of pangolins diagnosed by many anatomical synapomorphies, the family Manidae. This crown clade is sister to the family Patriomanidae, which includes two Tertiary taxa, Patriomanis americana and Cryptomanis gobiensis, within the superfamily Manoidea. The relationship of the Tertiary European pangolin Necromanis to these two families is unresolved. Within Manidae, the extant species are divided into three well-supported, monophyletic genera, Manis for the Asian pangolins, Smutsia for the African ground pangolins, and Phataginus for the African tree pangolins. The latter two form a monophyletic African assemblage, the subfamily Smutsiinae. The biogeographic implications of this phylogeny are examined. A European origin for Pholidota is strongly indicated. The fossil record of pangolins would seem to support a European origin for the modern forms, with subsequent dispersal into sub-Saharan African and then to southern Asia, and the phylogeny produced in this analysis is consistent with such a scenario.     

Changes in the digestibility of constituents of the diet in the rabbit]

Fiber digestibility of two diets (the first based on alfalfa dried, the second based on beet-pulp dried) with the same level of crude fiber and crude protein was measured on rabbits of 6, 7, 11, 13 and 17 weeks old. The age has no significative effect on digestibility (dry matter, organic matter, crude fiber) of the two experimental diets. The quantity of cellulose and hemicellulose digested was greater in rabbits on the pulp diet. Independantly of the diet hemicellulose is more digestible than cellulose. Expediency of use other analytical test than crude fiber in the nutritional requirements of rabbits is discussed.     

Ausscheidungen der Aminosäuren mit dem Harn und Kot von kolostomierten und nicht operierten Hennen — Beitrag zur Methode der Aminosäurenresorbierbarkeit

Veal calves aged 8 weeks were fed iso‐energetic amounts of milk replacers with either a low (7.1g of calcium/kg of air‐dry diet) or a high concentration of calcium (11.6g of calcium/kg of air‐dry diet) for a period of 10 weeks. The extra calcium was added in the form of calcium formiate. Final body weight of the two dietary groups was similar. Faeces were collected during the final week of the trial. The high calcium diet raised faecal dry matter output by 87% and faecal energy by 70%. The extra output of faecal dry matter was composed of 36% and 37% of crude fat and ash, respectively. The extra faecal energy output was for 75% in the form of crude fat. The high versus low calcium intake not only depressed apparent digestibility of total lipids but also that of crude protein, carbohydrates and ash. It is concluded that a high calcium intake by veal calves reduced energy availability without affecting body weight gain.     

Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows

Effects of fatty acids of linseed in different forms, on ruminal fermentation and digestibility were studied in dry cows fitted with ruminal and duodenal cannulas. Four diets based on maize silage, lucerne hay and concentrates (65/10/25 dry matter (DM)) were compared in a 4 × 4 Latin square design experiment where the diets were: control diet (C), diet RL supplied 75 g/kg DM rolled linseeds, diet EL supplied 75 g/kg DM extruded linseeds, and diet LO supplied 26 g/kg DM linseed oil and 49 g/kg DM linseed meal. The diets did not differ in total organic matter (OM) and fibre digestibility, in forestomach and intestinal OM digestibility, and in duodenal N flow. Microbial N duodenal flow tended to be lower for RL versus C diet (P<0.1). Extrusion did not reduce ruminal crude protein (CP) degradation in vivo and in situ. Volatile fatty acid concentration and pattern, and protozoa concentration in the rumen, did not vary among diets. Results confirm the absence of a negative effect of a moderate supply of linseed on rumen function, as well as no effect of extrusion on its ruminal CP degradability.     

Methane emission,digestive characteristics and faecal archaeol in heifers fed diets based on silage from brown midrib maize as compared to conventional maize

The aim of the present experiment was to compare silage prepared from maize having a brown midrib (BMR) mutation with control (CTR) maize to identify their effects on enteric methane emission, digesta mean retention time (MRT), ruminal fermentation and digestibility. In addition, the utility of archaeol present in faecal samples was validated as a proxy for methane production. Seven German Holstein heifers were fed total mixed rations with a maize-silage proportion (either BMR or CTR) of 920 g/kg dry matter (DM) in a change-over design. Heifers were fed boluses with markers to measure MRT; faeces were collected for 7 days and rumen fluid was collected on the penultimate day. Methane emission was measured in respiration chambers on one day. Data were analysed by t-test and regression analysis. DM intake did not differ between the two diets. The apparent digestibility of DM and most nutrients was unaffected by diet type, but apparent digestibility of neutral and acid detergent-fibre was higher in those heifers fed BMR than in those fed CTR. Comparisons between diets revealed no difference in particle or solute MRT in the gastro-intestinal tract and the reticulorumen. Concentrations of short-chain fatty acid and ammonia in rumen fluid and its pH were not affected by silage type. Independent of the mode of expression [l/d, l/kg DM intake, l/kg digested organic matter], methane emissions were not affected by maize-silage type, but with BMR, there was a trend towards lower methane production per unit of digested neutral detergent fibre than there was with CTR silage. Results of the present study show that feeding heifers BMR silage does not increase methane emissions despite a higher fibre digestibility as compared to CTR silage. Therefore, it is assumed that improvements in animal productivity achieved by feeding BMR silage, as some studies have reported, can be obtained without extra environmental cost per unit of milk or meat. Neither faecal archaeol content [µg/g] nor daily amount excreted [mg/d] is suitable to predict methane production in absolute terms [l per day]. However, faecal archaeol content has a certain potential for predicting the methane yield [l per kg DM intake] of individual animals.