136 research outputs found
Preference of goats (Capra hircus L.) for tanniniferous browse species available in semi-arid areas in Ethiopia
No full textThe objectives were to determine browse species preference of goats using dry matter intake (DMI) as a proxy, to compare preference when offered in combination with polyethylene glycol (PEG) and to establish relationships between browse species intake and chemical compositional data. Air-dried leaves of Acacia etbaica, Cadaba farinosa, Capparis tomentosa, Dichrostachys cinerea, Dodonaea angustifolia, Euclea racemosa, Maerua angolensis, Maytenus senegalensis, Rhus natalensis and Senna singueana were used. Two cafeteria trials, each lasting 10 days, were conducted using four local mature male goats of 2–2.5 years receiving a daily ration of grass hay (4% of body weight) and 200 g wheat bran. In trial 1, goats were offered 25 g of each browse species for a total of 30 min with intake, time spent on consumption and the number of visits to specific browse species recorded at 10-min intervals. In trial 2, the same procedure was followed except that 25 g of PEG 4000 was added to the daily wheat bran ration. Crude protein and neutral detergent fibre in browse species ranged from 69.0–245.5 to 159.8–560.6 g/kg dry matter (DM) respectively. Total phenols and total tannins contents ranged between 3.7–70.6 and 2.5–68.1 mg tannic acid equivalent/g DM, respectively, and condensed tannins 1.7–18.4 Abs550 nm/g DM. Preference indicators measured in the first 10 min of browse species intake differed significantly among browse species and with PEG (p < 0.0001). Principal components explained 69.9% of the total variation in browse species DMI. Despite the high tannin levels, D. cinerea, R. natalensis and A. etbaica were the most preferred species regardless of PEG presence. Tannin levels at the observed browse species DMI did not determine preference, instead, preference appeared to be based on hemicellulose. Determining browse species preference is essential to exploit them to improve nutrient utilization and control parasites in goats
In vitro digestibility and fermentability of selected insects for dog foods
No full text<p>Insects are considered as a sustainable protein source for future pet foods. Here we aimed to evaluate the protein quality of larvae of the black soldier fly (Hermetia illucens, BSF), housefly (Musca domestica, HF) and yellow mealworm (Tenebrio molitor, YMW) and to evaluate the fermentation characteristics of their indigestible fractions. Clean freeze-dried larvae were subjected to in vitro simulated canine gastric and small intestinal digestion. Undigested insect residues, shrimp chitin and fructooligosaccharides (positive control, FOS) were incubated for 48 h with inoculum with fresh feces from three dogs simulating large intestinal fermentation. The AA profiles differed among the larvae with proteins from BSF and YMW larvae containing more Val and less Met and Lys than HF larvae. The in vitro N digestibility of the HF (93.3%) and YMW (92.5%) was higher than BSF larvae (87.7%). The BSF larvae also had lower in vitro digestibility values for essential AA (92.4%) and non-essential AA (90.5%) compared to the larvae of the HF (96.6 and 96.5%) and YMW (96.9 and 95.3%). Gas production for FOS increased rapidly during the first 6 h. Low and similar amounts of gas were found for HF larvae and chitin whereas gas production slowly increased over 30 h and was slightly higher at 48 h for BSF than for chitin. Gas production for YMW increased considerably between 6 and 20 h. At 48 h, gas produced for undigested residues was comparable to shrimp chitin and lower than FOS (P </p
In vitro prediction of methane production by lactating dairy cows
No full textThe aim of this thesis was to determine the relationship (if any) between in vivo CH4 production obtained using climate controlled respiration chambers and in vitro CH4 production using the gas production technique. The in vitro techniques are routinely used to evaluate the nutritional quality of feeds and feed ingredients as they have an advantage of being less expensive, less laborious and allow maintenance of more precise experimental conditions than in vivo studies. It is well known that gas in the gas production (GP) technique is produced after the fermentation of the substrate where CO2 and methane (CH4) are produced as direct gas, and indirect gas is produced from the buffering of short chain fatty acids (SCFA). Studies investigating the relationship between in vitro and in vivo CH4 production by cows fed the same feed as substrate used in in vitro incubations are rare in the literature. It is important to have an accurate prediction on CH4 production of rations to be fed in practice. Therefore, the Dutch government financed a large program to determine the actual CH4 emission from dairy cattle in vivo, using climate respiration chambers (CRCs). This offered the unique opportunity to conduct parallel in vitro experiments with the aim to derive accurate in vitro prediction equations for CH4 production. Such equations can subsequently be used in practice to reduce CH4 emission. In vivo CH4 production of dairy cows cannot be predicted by in vitro CH4 production using the automated batch culture gas production technique, even if the cows are adapted to the substrate under investigation, The main predictors of CH4 production by dairy cattle are related to diet composition (NDF, CP and OM), In vitro CH4 production varies based on whether donor cows are adapted to a respective ration or not although the differences observed in thesis were minor
Effects of fibrolytic enzymes and lactic acid bacteria on fermentation quality and in vitro digestibility of Napier grass silage
No full textAn experiment was conducted to evaluate the effect of xylanase and cellulase derived from dried tomato pomace treated with Aspergillus niger and fermented juice of epiphytic of lactic acid bacteria (FJLB) on fermentative quality and in vitro digestibility of Napier grass silages. Thus, we treated Napier grass silage with or without fibrolytic enzymes (ENZ) in combination with or without FJLB. The pH values of silages treated with FJLB, but not ENZ, were found to be lower than the other silages during the ensiling process. The content of water soluble carbohydrates (WSC) of all silages was likely to decrease during fermentation in all silages. However, after 30 days of ensiling, the addition of ENZ resulted in higher WSC content when compared to the other treatments. At 30 day of ensiling, the crude protein of silage was higher in silage treated with FJLB. The gas production related to the soluble fraction was higher in silage treated with ENZ but total gas production was similar between treatments. The latter is in line the observation that the degradability of organic matter also was not different between treatments. It is concluded that neither the fermentation quality nor the in vitro digestibility of organic matter is improved when Napier grass is ensiled with both FJLB and fibrolytic enzymes compared with FJLB alone
In vitro methane and gas production with inocula from cows and goats fed an identical diet
No full textBACKGROUND: Fermentative capacity among ruminants can differ depending on the type of ruminant species and the substrate fermented. The aim was to compare in vitro cow and goat rumen inocula in terms of methane (CH4) and gas production (GP), fermentation kinetics and 72 h volatile fatty acids (VFA) production using the browse species Acacia etbaica, Capparis tomentosa, Dichrostachys cinerea, Rhus natalensis, freeze-dried maize silage and grass silage, and a concentrate as substrates. RESULTS: Total GP, CH4 and VFA were higher (P ≤ 0.008) in goat inoculum than cows across substrates. The half-time for asymptotic GP was lower (P < 0.0001) in phase 1 and higher (P < 0.012) in phase 2, and the maximum rate of GP was higher (P < 0.0001) in phase 1 and phase 3 (P < 0.0001) in goats compared to cows. Methane production and as a percentage of total GP was higher (P < 0.0001) and the half-time tended (P = 0.059) to be at a later time for goats compared to cows. CONCLUSION: Goat inoculum showed higher fermentative activity with a concomitant higher CH4 production compared to cows. This difference highlights the ability of goats to better utilise browse species and other roughage types
Immunomodulation by Processed Animal Feed : The Role of Maillard Reaction Products and Advanced Glycation End-Products (AGEs)
No full textThe immune system provides host protection to infection with pathogenic organisms, while at the same time providing tolerance upon exposure to harmless antigens. Thus, an impaired immune function is associated with increased susceptibility to infections with increased disease severity and thereby necessitating the therapeutic use of antibiotics. Livestock performance and feed efficiency, in addition to their health status, are dependent on the microbial load of their gut, the barrier function of the intestinal epithelium and the activity of the mucosal immune system, all of which can be modulated by dietary components. The majority of feeds that are consumed in pets and livestock have been processed. Processing promotes a non-enzymatic reaction between proteins and sugars called Maillard reaction (MR). Maillard reaction products (MRPs) and advanced Maillard reaction products (AGEs) determine taste, smell, and color of many food products therefore the MR is highly relevant for the feed industry. MRPs interact with different types of immune receptors, including the receptor for advanced glycation end products (RAGE) and immunomodulatory potential of feed proteins can be modified by Maillard reaction. This MR has become an important concern since MRPs/AGEs have been shown to contribute to increasing prevalence of diet-related chronic inflammatory states in the gut with negative health consequences and performance. The immunomodulatory effects of dietary MRPs and AGEs in livestock and pet animals are far less well-described, but widely considered to be similar to the relevant concepts and mechanisms obtained in the human field. This review will highlight immunological mechanisms underlying initiation of the innate and adaptive immune responses by MRPs/AGEs present in animal feeds, which are currently not completely understood. Bridging this knowledge gap, and taking advantage of progress in the human field, will significantly improve nutritional quality of feed and increase the prevention of diet-mediated inflammation in animals.</p
Protein and fat mobilization and associations with serum beta-hydroxybutyrate concentrations in dairy cows
No full textThe objective of this study was to obtain information on variation between dairy cows in muscle and fat tissue mobilization around parturition and to study the association between protein and fat mobilization and serum beta-hydroxybutyrate (BHBA) concentrations (hyperketonemia) in this period. Thirty-four cows kept under similar conditions at a university dairy farm (no experimental treatments) were monitored from 4 wk before until 8 wk after calving. Mobilization of muscle protein was investigated by analysis of plasma 3-methylhistidine concentrations (3-MH, analyzed by a recently developed HPLC tandem mass spectrometry method) and ultrasound measurements of longissimus muscle thickness. Mobilization of fat tissue was monitored by serum nonesterified fatty acid (NEFA) concentrations and ultrasound measurements of backfat thickness. Large variation was observed between cows in onset and duration of periparturient protein and fat mobilization. Plasma 3-MH concentrations and muscle thickness profiles indicated that protein mobilization started, on average, before parturition and continued until approximately wk 4 of lactation. Serum NEFA concentrations and backfat thickness profiles showed that fat mobilization occurred from parturition until the end of the study. Thus, muscle protein mobilization occurred in advance of fat mobilization in most cows from this study. We hypothesized that this might be due to a prepartum amino acid deficiency in the absence of negative energy balance. The incidence of hyperketonemia in this study was 16/34 = 47%. With the exception of 3 cows defined as having severe hyperketonemia, cows with lower 3-MH concentrations had higher serum BHBA concentrations. A possible explanation for this observation might be that higher mobilization of protein around calving might restrict ketone body production due to the higher availability of glucogenic precursors in the period of most severe negative energy balance and highest fat mobilization. The validity of this hypothesis needs to be confirmed, but data from this study indicate that further research on the role of protein mobilization in the etiology of hyperketonemia in dairy cows is needed
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Structural features of condensed tannins affect in vitro ruminal methane production and fermentation characteristics
No full textAn in vitro study was conducted to investigate the effects of condensed tannins (CT) structural properties, i.e. average polymer size (or mean degree of polymerization); percentage of cis flavan-3-ols and percentage of prodelphinidins in CT extracts on methane production (CH4) and fermentation characteristics. CT were extracted from eight plants in order to obtain different CT types: black currant leaves, goat willow leaves, goat willow twigs, pine bark, red currant leaves, sainfoin plants, weeping willow catkins and white clover flowers. They were analysed for CT content and CT composition by thiolytic degradation, followed by HPLC analysis. Grass silage was used as a control substrate. Condensed tannins were added to the substrate at a concentration of 40 g/kg, with or without polyethylene glycol (+ or −PEG 6000 treatment) to inactivate tannins, and then incubated for 72 h in mixed buffered rumen fluid from three different lactating dairy cows per run. Total cumulative gas production (GP) was measured by an automated gas production system. During the incubation, 12 gas samples (10 μl) were collected from each bottle headspace at 0, 2, 4, 6, 8, 12, 24, 30, 36, 48, 56 and 72 h of incubation and analyzed for CH4. A modified Michaelis–Menten model was fitted to the CH4 concentration patterns and model estimates were used to calculate total cumulative CH4 production (GPCH4). Total cumulative gas production and GPCH4 curves were fitted using biphasic and monophasic modified Michaelis-Menten models, respectively. Addition of PEG increased GP, GPCH4, and CH4 concentration compared to the −PEG treatment. All CT types reduced GPCH4 and CH4 concentration. All CT increased the half time of GP and GPCH4. Moreover, all CT decreased the maximum rate of fermentation for GPCH4 and rate of substrate degradation. The correlation between CT structure and GPCH4 and fermentation characteristics showed that the proportion of prodelphinidins within CT had the largest effect on fermentation characteristics, followed by average 27 polymer size and percentage of cis-flavan-3-ols
Measurement of allergen-specific IgG in serum is of limited value for the management of dogs diagnosed with cutaneous adverse food reactions
No full textConflicting results have been reported in the literature in terms of the usefulness of serological testing for IgG against food allergens in dogs with cutaneous adverse food reaction (CAFR). The aim of the present study was to evaluate the suitability of a commercially available IgG ELISA for identifying food allergens in dogs, by challenging dogs with specific food ingredients, selected on the basis of IgG reactivity in serum samples. A total of 24 adult dogs with CAFR were enrolled into the study and 16 healthy dogs were included as a control group. Blood samples were obtained for measurement of specific IgG antibodies against 39 commonly used pet food ingredients by ELISA. Participating owners were surveyed to obtain information on their pet's dietary history. Eleven healthy control dogs and 12 dogs with CAFR were subsequently challenged in a blinded cross-over design experiment with both positive and negative food ingredients, selected on the basis of the ELISA test results. There was substantial individual variation in ELISA test results to the various food allergens, but no significant difference in IgG reactivity comparing the CAFR and control groups. None of the control dogs developed any clinical signs of an allergic reaction during the dietary challenge study. In the CAFR group, six of 12 dogs developed clinical signs after the negative challenge, and two of nine dogs developed clinical signs after the positive challenge. It was concluded that the ELISA test for dietary allergen-specific IgG is of limited value in the management of dogs with CAFR
Response of saliva Na/K ratio to changing Na supply of lactating cows under tropical conditions
No full textBACKGROUND: Factorial determination of the sodium (Na) requirement of heat-stressed lactating cows is hindered by accurate estimates of the Na losses through sweat. Direct studies, therefore, may be needed requiring information on the time course of healthy animals to become Na depleted and the subsequent rate of repletion. The rate of Na depletion and subsequent rate of Na repletion with two levels of dietary Na to lactating dairy cows housed under tropical conditions were investigated using the salivary Na/K. RESULTS: The 12 lactating cows (salivary Na/K ratio 14.6) rapidly developed clinical signs of Na deficiency, including pica, polyuria and polydipsia, reduced body weight and reduced milk yield when fed a low-Na ration (0.33 g kg(-1) dry matter (DM)) for 3 weeks. Deficiency symptoms were associated with a rapid decrease in salivary Na/K ratio to 6. CONCLUSION: A daily Na intake of heat-stressed lactating cows to a ration intake of 1.6 g Na kg(-1) DM was insufficient to restore Na deficiency. One week was sufficient to deplete heat-stressed lactating cows of Na, allowing for rapid dose-response studies utilizing the salivary Na/K ratio as a parameter for Na status of cows under tropical conditions. © 2016 Society of Chemical Industry
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