Rumen Fluid from Slaughtered Animals: A Standardized Procedure for Sampling, Storage and Use in Digestibility Trials.

Digestibility trials need a viable rumen fluid as inoculum to degrade feeds. The variability of rumen fluid depends on the animal's diet, while its viability is greatly influenced by the sampling and handling procedures. In this article, we present a replicable protocol for sampling the rumen fluid from slaughtered animals for in vitro digestibility trials. A detailed list of the tools and a step-by-step standardized procedure for the collection, storage and the transportation of the rumen fluid from the slaughterhouse to the laboratory is presented. We also describe a digestibility trial for establishing the maximum storage time of rumen fluid from sampling to its use. The results show that the rumen fluid, collected and maintained according to the proposed protocol, can be stored and used from 30 to 300 min from sampling without significantly compromising the fermentative activity of the microbial population.

Arabian mare's milk characterisation and clotting ability.

The objective of this study is to characterize purebred Arab mares' milk through monitoring its physicochemical and microbiological composition during different lactation stages and to test its ability to coagulate. Sixteen purebred Arabian mares were selected among 45 mares with approximately the same foaling dates. Milk samples were collected once a week for each mare during 4 months of lactation and analysed in three replicates for physicochemical composition, nitrogen fractions, somatic cell count and total bacterial count. Coagulation assays were carried out in triplicates on fresh mare's milk using increasing doses of calf rennet, starter (Streptococcus thermophilus) and CaCl2. Arab mare's milk is characterized by an alkaline pH, low-fat and protein contents and high lactose content. The somatic cell and bacterial counts are very low, indicating good health status of mares. Fat and protein contents decreased as the stage of lactation progressed. However, as lactation number increased, fat level tended to increase while protein level tended to decrease. Clotting assays proved that it is possible to coagulate Arabian mare's milk using appropriate doses of calf rennet and starter, while respecting the coagulation procedures and parameters.

Comparison of In Vivo and In Vitro Digestibility in Rabbits.

The apparent dry matter digestibility of diets for rabbits was measured in vivo (ADMDvv) and in vitro with the Ankom DaisyII Incubator. Four diets were tested: low fiber (LF), LF + 5% of pregerminated fenugreek seeds (PGFS) (LF5), LF + 10% PGFS (LF10), and high fiber (HF). For the ADMDvv, feces samples were collected from 56 White New-Zealand × Californian rabbits fed the 4 diets; animals were randomly allocated into 4 groups and housed in individual cages. For the in vitro trial, 3 methods were tested: fecal inoculum (FA) with Kansans State buffer; fecal inoculum with artificial saliva (FB); and multienzyme (ENZ). Fecal inocula were collected at slaughtering from the distal colon of rabbits fed ad libitum the LF diet. For FA and FB methods, the digestibility was measured at 36 and 48 h. The in vitro methods ranked the apparent dry matter digestibility of diets in the same order as in vivo, but ENZ values were always higher than FA and FB at 36 and 48 h. The prediction equations of in vivo digestibility with the ENZ method showed higher coefficient of determination (R2 = 0.69) and lower SE (0.190) than FA and FB; also, reproducibility was higher with ENZ (CV = 3.1%). In conclusion, different methods can be applied to the Ankom DaisyII Incubator to study the digestibility in rabbits. In our trial, the better reproducibility was observed with the multienzyme method than FA and FB were probably related to the variability of inocula.

Pilot Study of the Effects of Polyphenols from Chestnut Involucre on Methane Production, Volatile Fatty Acids, and Ammonia Concentration during In Vitro Rumen Fermentation.

Nutritional strategies can be employed to mitigate greenhouse emissions from ruminants. This article investigates the effects of polyphenols extracted from the involucres of Castanea mollissima Blume (PICB) on in vitro rumen fermentation. Three healthy Angus bulls (350 ± 50 kg), with permanent rumen fistula, were used as the donors of rumen fluids. A basic diet was supplemented with five doses of PICB (0%-0.5% dry matter (DM)), replicated thrice for each dose. Volatile fatty acids (VFAs), ammonia nitrogen concentration (NH3-N), and methane (CH4) yield were measured after 24 h of in vitro fermentation, and gas production was monitored for 96 h. The trial was carried out over three runs. The results showed that the addition of PICB significantly reduced NH3-N (p < 0.05) compared to control. The 0.1%-0.4% PICB significantly decreased acetic acid content (p < 0.05). Addition of 0.2% and 0.3% PICB significantly increased the propionic acid content (p < 0.05) and reduced the acetic acid/propionic acid ratio, CH4 content, and yield (p < 0.05). A highly significant quadratic response was shown, with increasing PICB levels for all the parameters abovementioned (p < 0.01). The increases in PICB concentration resulted in a highly significant linear and quadratic response by 96-h dynamic fermentation parameters (p < 0.01). Our results indicate that 0.2% PICB had the best effect on in-vitro rumen fermentation efficiency and reduced greenhouse gas production.

Comparison of In Vivo and In Vitro Digestibility in Donkeys.

We compared in vivo and in vitro dry matter (DM) and neutral detergent fiber (NDF) digestibility in donkeys using feces as microbial inoculum. Four donkeys were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The animals were fed two types of hay, with or without flaked barley. For the in vivo procedure, total feces were collected for 6 days from each donkey; digestibility was calculated as the difference between ingested and excreted DM and NDF. For the in vitro procedure, donkey feces were buffered and used as microbial inoculum in an Ankom DaisyII Incubator; digestibility was estimated after 60 h of incubation. In vivo results showed that the addition of barley to hays did not change the digestibility values. In vivo estimates were higher than in vitro ones. The equations used to predict in vivo estimates from in vitro data were not reliable (R2 = 0.47 and 0.21; P = 0.003 and 0.078 for NDF and DM digestibility, respectively). Further studies need to evaluate different sample size and digestion times.

In Vitro Techniques Using the DaisyII Incubator for the Assessment of Digestibility: A Review.

This review summarises the use of the Ankom DaisyII incubator (ADII; Ankom Technology Corporation Fairport, NY, USA), as presented in studies on digestibility, and its extension to other species apart from ruminants, from its introduction until today. This technique has been modified and adapted to allow for different types of investigations to be conducted. Researchers have studied and tested different procedures, and the main sources of variation have been found to be: the inoculum source, sample size, sample preparation, and bag type. In vitro digestibility methods, applied to the ADII incubator, have been reviewed, the precision and accuracy of the method using the ADII incubator have been dealt with, and comparisons with other methods have been made. Moreover, some hypotheses on the possible evolutions of this technology in non-ruminants, including pets, have been described. To date, there are no standardised protocols for the collection, storage, and transportation of rumen fluid or faeces. There is also still a need to standardise the procedures for washing the bags after digestion. Moreover, some performance metrics of the instrument (such as the reliability of the rotation mechanism of the jars) still require improvement.

Effects of Dietary Quebracho Tannin on Performance Traits and Parasite Load in an Italian Slow-Growing Chicken (White Livorno Breed).

Tannins have shown numerous biological activities and are very appreciated in food animal production, especially for their antimicrobial, antiparasitic, antioxidant, anti-inflammatory and antivirus effects. The aim of the present study was to evaluate the effect of two levels of dietary Quebracho tannin (QT) on growth and performance traits, and possible effects on intestinal parasite load in Italian White Livorno pullets. A 140-day trial was carried out on 180 35-day-old females, fed on two levels of dietary QT inclusion: 0%, 1% and 2%. Birds were reared under free-range conditions. Dietary Quebracho tannin may be used up to 1% in growing female White Livorno chickens without any adverse effects. The results observed in this study on the use of dietary QT at 2% might have not reflected the real effect on performance traits due to the initial inclusion of dietary QT at 3%. Nevertheless, by reducing QT to 2%, a progressive normalization of body weight gain, feed intake and feed conversion ratio was observed, resulting in compensatory growth. QT was demonstrated to drastically reduce fecal outputs of Nematodes eggs (Ascaridia spp. and Heterakis spp.) and Coccidia oocytes (Eimeria spp.). The inclusion of 2% produced highly dry droppings.

In Vitro Digestibility Measurement of Feedstuffs in Donkeys Using the DaisyII Incubator.

Successful studies on in vitro digestibility measurement of feedstuffs with fecal inoculum have been reported for horses, whereas data on donkeys are currently lacking. In this study, we evaluated the use of the DaisyII Incubator for in vitro digestibility measurement of feedstuffs using donkey feces as source of microbial inoculum. The method was tested using seven feedstuffs commonly used in donkey diets (alfalfa, bromegrass, ryegrass, and timothy hays; wheat bran and wheat straw; barley grains). Feces were obtained from four female donkeys, and incubations were carried out at 1-week intervals for four consecutive weeks. Two bags of each feedstuff were incubated in digestion vessels containing a buffer/feces solution (90:10). In vitro apparent dry matter digestibility (DMD), true dry matter digestibility (IVTD), and neutral detergent fiber digestibility (NDFD) were evaluated at four incubation times: 30, 48, 60, and 72 hours. All digestibility parameters significantly increased from 30 to 72 hours of incubation. At 72 hours of incubation, the within-laboratory repeatability and reproducibility of the method were 2.7% and 5.0% for DMD and 1.6% and 3.9% for IVTD, respectively. The method was less repeatable and reproducible for NDFD (4.5% and 10.4%, respectively).

Effect of ruminally unprotected Echium oil on milk yield, composition and fatty acid profile in mid-lactation goats.

This study investigated the effects on goat milk yield and composition of a diet supplemented with Echium plantagineum oil (EPO). Twenty-four mid-lactation multiparous Camosciata goats were divided into two balanced groups and fed for 44 d a diet based on hay and concentrate, supplemented (EPO group, Echium) or not (CON group, control) with 40 ml of ruminally unprotected EPO. Individual milk yield was recorded and individual milk samples were collected at 11, 22, 33, and 44 d after supplementation. Milk samples were analysed for milk components and fatty acids (FA). Data were statistically analysed by repeated-measures analysis of variance. Milk yield, protein and lactose contents were significantly higher in EPO than CON group. The inclusion of EPO significantly decreased total saturated FA and total branched-chain FA, and contemporarily sharply increased trans biohydrogenation intermediates (P ⩽ 0.001). Milk concentration of α-linolenic, stearidonic and γ-linolenic acids increased by 23, 1000 and 67%, respectively (P ⩽ 0.001). Due to extensive ruminal biohydrogenation, their apparent transfer rate was less than 3%. As a consequence, the milk concentrations of very long-chain (VLC) polyunsaturated fatty acids (PUFA), such as eicosapentaenoic (20:5 n-3) and dihomo-γ-linolenic (20:3 n-6) acids, significantly increased with EPO treatment, but values remained very low. Docosahexaenoic acid (22:6 n-3) was undetectable in all analysed milk samples. Results show that ruminally unprotected EPO can enhance milk yield and protein and improve the overall goat milk FA profile. However, this kind of supplementation cannot be considered a valuable strategy to develop goat functional dairy products enriched with VLC n-3 PUFA for human consumption.