Dry Digestibility Research Articles

Accumulation and health risk of heavy metals in local and imported fish (rastrelliger kanagurta) sold in Shah Alam, Selangor

Global aquatic ecosystems are becoming increasingly polluted with heavy metals posing health concerns associated with fish consumption. This study aims to determine the concentrations of cadmium (Cd) and lead (Pb) in local and imported fish (Rastrelliger kanagurta), and its potential human health risk. Total local and imported fish (60 samples) were randomly selected and purchased from ten different supermarkets in Shah Alam, Selangor. Cd and Pb concentrations were assessed by using dry ashing-acid digestion technique and analysed with atomic absorption spectrometry (AAS). The analytical results shows that the mean concentration of Cd in local and imported fish (Rastrelliger kanagurta) were 0.487 ± 0.25 mg/kg and 0.267 ± 0.11 mg/kg, respectively. The mean concentration of Pb in local fish was higher at 2.774 ± 1.46 mg/kg compared to the imported fish (1.482 ± 0.81 mg/kg). Further analysis indicated that there are significant differences (p < 0.05) for both Cd and Pb levels in local and imported fish (Rastrelliger kanagurta) sold within Selangor supermarkets. The concentration of Pb in local fish sold from supermarkets failed to comply with all the standards guidelines. The hazard quotient (HQ) used for health risk assessment of Pb and Cd was found to be < 1 (HQ < 1) for imported fish and potential risk for local fish (HQ > 1). The study reveals that the local fish are not totally safe for consumption and the pollution concentrations are on the borderline but can be treated.

Effect of Aspergillus oryzae on ruminal fermentation, feed intake and dry matter digestibility in cows fed forage-based diets

The present study was conducted to investigate the effect of Aspergillus oryzae inclusion on ruminal fermentation, feed intake and dry matter (DM) apparent digestibility in cows fed Cenchrus purpureus forage and concentrate. Cows were randomly assigned in a replicated 4 × 4 Latin square design, into four treatments: control and three doses of A. oryzae culture (1, 2 and 3 g/d). Experimental periods had 21 days, in which 14 days were allowed for treatment adaptation and 7 days for sampling. Addition of 2 g/d increased (p = 0.0054) total anaerobic bacteria. For cellulolytic bacteria and fungal populations increases (p < 0.0001) with all doses were observed. Highest concentrations of total short chain fatty acids (SCFAs), acetate, isovalerate and valerate were observed with 2 g/d of additive. Propionate concentration and acetate: propionate (Ac:Pr) ratio were unaffected by treatments. A. oryzae addition did not modify ruminal pH. A decrease of ammonia-N was observed with 2 g/d of additive. Dry matter intake and apparent digestibility of DM were increased (p = 0.0171 and p = 0.0023, respectively) with the fungal culture addition. It is concluded that Aspergillus oryzae strain H/6.28.1 stimulates ruminal fermentation and improves feed intake and dry matter apparent digestibility in cows feeding with Cenchrus purpureus forage and concentrate.

Selective extraction of sodium from red mud by dry digestion

The strong alkalinity of red mud prevents its application as soil aggregates, adsorbing materials, fillers, and building materials. Direct acid leaching is an effective method for dealkalization of red mud. However, the formation of silica gel in the process causes significant processing difficulties. Herein, a dry digestion method was introduced to red mud for the selective recovery of Na with suppressed formation of silica gel. The optimum conditions of dry digestion and leaching were obtained as follows: temperature of 50 °C, H2SO4 concentration of 1 mol/L, curing time of 30 min, and leaching solid–liquid ratio of 1:3. Almost 85% Na was leached, where Si dissolution was suppressed to 0.7% and no silica gel was formed. X-ray diffraction (XRD) and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS) results revealed that the large particles of quartz with circular crystals and gypsum with bar-shaped crystals were generated during dry digestion. The particle size of red mud after leaching increased and formed a reunion phenomenon, which improved the filtration performance. Compared with the traditional process, the proposed dealkalization process is conducive to subsequent utilization.

Degradation of bioplastics in organic waste by mesophilic anaerobic digestion, composting and soil incubation

The aim of the study was to assess the effects of high concentrations (10 % w/w, data projected for 2030) of commercial bioplastics, i.e. starch based shopping bags (SBSB) and polylactic acid (PLA) tableware, in the organic fraction of municipal solid wastes (MSW) on compost quality obtained by pilot-scale dry mesophilic anaerobic digestion and subsequent composting of the digestate.After the biological processes, 48.1 % total solids (TS) of SBSB and 15 % TS of PLA degraded, resulting in a high bioplastics content (about 18 % TS) in compost. Subsequent compost incubation in soils indicated that bioplastics degraded by pseudo-zero order kinetics (0.014 and 0.010 mg C cm−2 d-1 for SBSB and PLA, respectively), i.e. complete degradation was expected in 1.6 years (SBSB) and 7.2 years (PLA), confirming the intrinsic biodegradability of bioplastics. Nevertheless, enhancing the rate and amount of bioplastics degradation during waste management represents a goal to decrease the amount of bioplastics reaching the environment.

Influence of integrated crop-livestock-forest on morphological composition and nutritional value of Marandu palisadegrass under continuous grazing

This study characterizes the changes in leaf mass, morphological composition and nutritional value of leaf blades of palisadegrass (Urochloa brizantha cv. Marandu) under continuous grazing in the first year of implementation of pasture and after second year of the eucalyptus planting in an Integrated Crop-Livestock System and Integrated Crop-Livestock-Forest, which were tested in the four seasons. The experimental design was in random blocks, with three treatments: Crop-Livestock System (ICL) and Integrated Crop-Livestock-Forest with two eucalyptus tree densities (ICLF-1L, 196 eucalyptus trees ha-1 and ICLF-3L, 448 eucalyptus trees ha-1) and four replicates. Sixty castrated Nellore cattle with initial weight of 235.43 ± 25.46 kg and mean age of 16 ± 2.81 months were used during the growing phase under continuous grazing. The agronomic variables were: total dry mass of forage, leaves, stem and dead material; leaf: stem and live: senescent material ratios; and accumulation rate. The leaf: stem and live: senescent material relation did not obtain any difference between the evaluated systems. Dry matter, crude protein, fiber fractions and digestibility of leaf blades were evaluated. Dry mass of the forage (6775 kg ha-1), stem (2175 kg ha-1), senescent material (3175 kg ha-1) and dry matter content (28.6%) were greater in the ICL, whereas crude protein (11.3%) was greater in the ICLFs. On the other hand, accumulation rate and dry mass of leaf blades did not change between systems. Thus, until the first year of grazing, tree systems have advantages, because the forage production (accumulation rate) and leaf mass are similar to those of plants in full sun, besides showing higher nutritional value.

VALIDATION OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF INORGANIC AND ORGANIC ARSENIC IN FISH SAUCE BY HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROSCOPY

The validation of an analytical method was carried out for the determination of arsenic components in fish sauce by HG-AAS. The total arsenic content (tAs) was analyzed after digesting the sample by dry and wet combined digestion method in a Teflon flask at 450 °C and then reducing As (V) to As (III) with a mixture of reducing agents KI/ascorbic acid. For inorganic arsenic content (iAs), the sample was hydrolyzed with HCl solution for 14 hours, converted As (V) to As (III), then reacted with hydrazine 1.5%. Extracted in CHCl3 and re-extracted in HNO3. The organic arsenic content (oAs) was calculated by the difference tAs and iAs. Determined the linear concentration range 2 - 30 μg/L and the standard curve was y = 0.0128x + 0.0007 with R² = 0.9996 at the concentration range 2 - 20 μg/L. LODs, LOQs for total and inorganic arsenic contents were found and all they were 0.015 mg/L and 0.05 mg/L, respectively. For total arsenic, the recovery efficiencies on the organic arsenic standard and inorganic arsenic standard all ranged from 81 to 109%;...

Use of Inoculum, Water and Percolate as Strategy to Avoid Inhibition on Dry-Batch Anaerobic Digestion of Organic Fraction of Municipal Solid Waste

The impact of inoculum to substrate ratio (I:S) and the addition of water and percolate on stopping inhibition in dry batch anaerobic digestion of organic fraction municipal solid waste (OFMSW) was investigated. In particular, ratios of I:S from 1:2 to 1:16 and total solid contents from 40 to 25% with water and percolate addition were analysed. Tested I:S did not avoid acidification of the anaerobic digesters (ADs), and the highest biogas and methane production (16.2 and 1.7 L/kg VSadded, respectively) was achieved with the 1:4 ratio. Water addition was also insufficient to avoid acidification, and while biogas increased as TS decreased, 40.9 L/kg VSadded for 25% TS, methane yield remained low at 1.2 L/kg VSadded due to the inhibition of methanogenic archaea. Percolate addition proved a suitable strategy to increase pH buffering, with an increased methane production of 199.4 L/kg VSadded at similar TS ranges (27%). Impact on kinetics of methane formation was assessed by kinetic modelling with logistic model identified as the better fit for most of the ADs. Shorter lag phases were observed as TS were reduced, regardless of the acidification, as mass transfer limitations were reduced at the beginning of the batch, but an increase was observed when percolate was used instead of water. Increases of the maximum methane rate (Rmax) was also achieved with TS reduction, but only when acidification was avoided. This study has highlighted the need to profile percolate composition during batch digestion in order to balance recirculation of nutrients, microbial communities and toxic compounds.Graphic

Triangulation of microbial fingerprinting in anaerobic digestion reveals consistent fingerprinting profiles

The anaerobic digestion microbiome has been puzzling us since the dawn of molecular methods for mixed microbial community analysis. Monitoring of the anaerobic digestion microbiome can either take place via a non-targeted holistic evaluation of the microbial community through fingerprinting or by targeted monitoring of selected taxa. Here, we compared four different microbial community fingerprinting methods, i.e., amplicon sequencing, metaproteomics, metabolomics and cytomics, in their ability to characterise the full-scale anaerobic digestion microbiome. Cytometric fingerprinting through cytomics reflects a, for anaerobic digestion, novel, single cell-based approach of direct microbial community fingerprinting by flow cytometry. Three different digester types, i.e., sludge digesters, digesters treating agro-industrial waste and dry anaerobic digesters, each reflected different operational parameters. The α-diversity analysis yielded inconsistent results, especially for richness, across the different methods. In contrast, β-diversity analysis resulted in comparable profiles, even when translated into phyla or functions, with clear separation of the three digester types. In-depth analysis of each method's features i.e., operational taxonomic units, metaproteins, metabolites, and cytometric traits, yielded certain similar features, yet, also some clear differences between the different methods, which was related to the complexity of the anaerobic digestion process. In conclusion, cytometric fingerprinting through flow cytometry is a reliable, fast method for holistic monitoring of the anaerobic digestion microbiome, and the complementary identification of key features through other methods could give rise to a direct interpretation of anaerobic digestion process performance.

بررسی مقایسه ای فلفل قرمز با محرکهای رشد تجاری بر عملکرد جوجههای گوشتی در شرایط تنش گرمایی

Effect of red pepper in comparison to commercial growth promoters, Biostrong and Oleobiotec, on growth performance, nutrient digestibility, and other traits of broilers under heat stress conditions using 200 day-old broiler chickens mixed male and female of ArborAcers strain in a completely randomized design with four treatments, five replications and ten chickens per replicate were evaluated. Treatments included a basal diet without additives and a basal diet containing 10, 0.1, 0.15 g/kg red pepper, Biostrong, and Oleobiotec,respectively. At the beginning of third week, the birds were exposed to heat stress for six hours per day. During the 42 days of the experiment, the mean minimum and maximum temperatures were 25°C and 33°C. Feed intake, weight gain, feed conversion ratio, the weight of internal organs, caecal microflora, and precaecal nutrient digestibility were measured for the heat stress period. The use of red pepperimproved the feed conversion ratio and daily weight gain in grower and finisher periods and increased protein, lipid, and dry matter precaecal digestibility, the relative weight of bursa of Fabricius, spleen, and gizzard, and decreased the Ecoli population in caecum compared to the control treatment (P≤0.05). Biostrong and Oleobiotec did not affect growth performance, prececal nutrient digestibility, and the E.colipopulation. Overall, using the red pepper in the diet of broilers compared to commercial growth promoters reduced the adverse effects of heat stress on growth performance, nutrient digestibility, and caecal microflora.

Advances in Understanding of the Application of Unit Operations in Metallurgy of Rare Earth Elements

Unit operations (UO) are mostly used in non-ferrous extractive metallurgy (NFEM) and usually separated into three categories: (1) hydrometallurgy (leaching under atmospheric and high pressure conditions, mixing of solution with gas and mechanical parts, neutralization of solution, precipitation and cementation of metals from solution aiming purification, and compound productions during crystallization), (2) pyrometallurgy (roasting, smelting, refining), and (3) electrometallurgy (aqueous electrolysis and molten salt electrolysis). The high demand for critical metals, such as rare earth elements (REE), indium, scandium, and gallium raises the need for an advance in understanding of the UO in NFEM. The aimed metal is first transferred from ores and concentrates to a solution using a selective dissolution (leaching or dry digestion) under an atmospheric pressure below 1 bar at 100 °C in an agitating glass reactor and under a high pressure (40–50 bar) at high temperatures (below 270 °C) in an autoclave and tubular reactor. The purification of the obtained solution was performed using neutralization agents such as sodium hydroxide and calcium carbonate or more selective precipitation agents such as sodium carbonate and oxalic acid. The separation of metals is possible using liquid (water solution)/liquid (organic phase) extraction (solvent extraction (SX) in mixer-settler) and solid-liquid filtration in chamber filter-press under pressure until 5 bar. Crystallization is the process by which a metallic compound is converted from a liquid into a crystalline state via a supersaturated solution. The final step is metal production using different methods (aqueous electrolysis for basic metals such as copper, zinc, silver, and molten salt electrolysis for REE and aluminum). Advanced processes, such as ultrasonic spray pyrolysis, microwave assisted leaching, and can be combined with reduction processes in order to produce metallic powders. Some preparation for the leaching process is performed via a roasting process in a rotary furnace, where the sulfidic ore was first oxidized in an oxidic form which is a suitable for the metal transfer to water solution. UO in extractive metallurgy of REE can be successfully used not only for the metal wining from primary materials, but also for its recovery from secondary materials.

DETERMINATION OF TRACE ELEMENTS IN SOME BRANDS OF GREEN TEA USING WET DIGESTION, INFUSION AND DRY ASHING METHODS

The concentrations of trace elements (Cu, Zn, Fe, Mn and Ni) in some commercially available brands of green tea sold within Katsina metropolis coded (SGT, HGT, LGT, AGT and GGT) were determined using wet acid digestion, water infusion, and Dry Ashing methods by Atomic Absorption Spectroscopy (AAS). Among the trace elements analyzed Nickel and Manganese recorded the highest value ranged 1.0 – 3.5 mg kg-1 and1.0 – 5.5 mg kg-1 in dry ashing and wet digestion respectively. Fortunately, almost all the elements analyzed were within the standard permissible limit of WHO. The content of trace elements was found highest in the Dry Ashing method and lowest values recorded in tea infusion. The contributory factors responsible for the differences found in tea samples could be from a varying concentration of metals in the soil, conditions of cultivation and preparations, and these vary between both countries of origin and for the type of tea. Further work is recommended on these brands to study other important parameters

Effect of Adding Watermelon Juice, Vitamin E-Selenium, and Vitamin C into the Drinking Water on Growth Performance, Internal Organs’ weight and Prececal Nutrient Digestibility in Broilers under Heat Stress

This study investigated the effect of adding watermelon juice, vitamin Eselenium and vitamin C to the drinking water on growth performance, internal organs’ weight, and prececal nutrient digestibility in broilers under heat stress. Two hundred and fifty Hubbard F15 day-old broilers were allocated to five treatments with five replicates of 10 broilers per each replicate, based on a completely randomized design. The birds in the control treatment did not receive any supplement in drinking water and reared in thermoneutral temperature. Birds in the other four treatments received watermelon juice at 60% or 30%, vitamin C at 50 mg/L, or vitamin E-Selenium at 1 mL/L of drinking water during the heat stress period. Heat stress applied for 9 hours from day 12 onward. Results indicated birds that received 60% watermelon juice had similar body weight and feed intake compared to control birds. The relative weight of proventriculus, intestine length, and prececal dry matter nutrient digestibility was significantly higher in 60% watermelon juice treatment than other treatments. It is concluded that watermelon juice supplementation at 60% concentration into the drinking water could improve the performance of birds reared under heat stress as a result of restoring water and feed intake and also better prececal dry matter digestibility.

Coconut (Cocos nucifera) and Salak (Salacca zalacca) polysaccharides in the diets of Escherichia coli-challenged broilers

Palm polysaccharides were believed to contain mannose monosaccharides that are beneficial as an antibiotic replacer for poultry. This experiment was conducted to study the effect of coconut and salak polysaccharides on growth performance, excreta dry matter, digestibility, and bursa of Fabricius weight of E. coli challenged broilers. A total of 140-day old unsexed broiler Cobb chicks were used as experimental birds for 4 weeks. During the first week, the chicks were allocated in five brooder pens and transferred into 20 pens on day 8. The broiler chicks were offered 5 different experimental rations. The rations were control basal diet (T1), basal diet added with antibiotic avilamycin (T2), basal diet added with commercial yeast oligosaccharides (T3), basal added with coconut polysaccharides (T4), and basal diet added with Salak (snake fruit) polysaccharides (T5). To protect the birds from New Castle diseases, vaccination was done on day 3. On day 14, the birds were challenged against E. coli for three consecutive days. Plastic feeders and drinkers were put in the pen. The experiment used a completely randomized design with five different rations, four replicate pens of 7 birds each. The data were subjected to the analysis of variance. Any significant differences detected in the variance analysis were then tested with the least significant difference test. Results indicated that after challenged with E. coli, birds fed the basal diet had lower body weight gain, mortality, excreta dry matter, and carcass percentage, but higher in FCR and bursa of Fabricius weight than the birds fed T2, T3, T4, and T5 diets. Feed intake of the E. coli challenged broilers were lower than those of broilers fed the T3 diet. Feed digestibility was not affected by the treatment diets. In conclusion, the addition of feed additives either antibiotic or palm polysaccharides could enhance the growth performance, carcass percentage, and excreta dry matter of the E. coli challenged broilers.

An investigation on chemical/mineral compositions, ruminal microbial fermentation, and feeding value of some leaves as alternative forages for finishing goats during the dry season

Finding new fodder resources with moderate to high nutritional value that are cheaper and available is one of the most challenges in livestock industries. Hence, the nutritive value of some tree leaves (quince, pear, olive, mirabelle plum, greengage, sour cherry, and persimmon) was investigated by different laboratories and in vitro methods. Also, partial substitution of alfalfa and corn silage (50%) with these leaves was investigated using forty-eight goats in a randomized complete block design in vivo. Highest total phenol and tannin contents were obtained in quince (p < 0.001). Greengage (146.37 g/kg DM) and persimmon (136.96 g/kg DM) exhibited the highest crude protein, respectively (p < 0.001). Calcium content (19.82 g/kg DM) was highest in persimmon leaves (p < 0.001). Greengage (66.07 mmol/L) and mirabelle plum (65.58 mmol/L) produced more total volatile fatty acids in the culture medium, respectively (p < 0.001). Potential gas production ranged from 39.65 mL for pear to 55.32 mL mirabelle plum. Sour cherry had the highest acid–base buffering capacity (183.73 mEq × 10–3, p < 0.001). Highest dry matter intake (1087 g/day) and crude protein digestibility (70.80 %) were observed in diets containing greengage (p < 0.001). Total antioxidant capacity of serum increased when olive, quince, and persimmon were considered in goats feeding (p < 0.001). Although all studied leaves can be fed in diets of goats without deleterious effects on performance, serum, and hematology parameters, in vivo and in vitro results indicated that greengage in terms of nutritive value was superior to other studied leaves.

Influence of Achyranthes japonica extracts supplementation in the diets of finishing pigs.

Herbs and their extracts have been used for a long time in animal industries as alternatives to an antibiotic. This study was evaluated the effects of dietary supplementation of Achyranthes japonica extracts (AJE) on the performance and production parameters in finishing pigs. Totally, 100 pigs with an average body weight of 50.33±4.61kg were used as a 10-week feeding trial. Pigs (five replicates, three barrows and two gilts per pen) were allotted randomly to four treatments as the addition of 0%, 0.05%, 0.10% and 0.20% of AJE in basal diets. A linear increase (p<.05) in average daily gain was observed during week 5, week 10 and overall period, and a linear decrease (p<.05) was observed in the feed conversion ratio during week 5. A linear increase (p<.05) in dry matter, protein digestibility and faecal ammonia emission on week 5 and week 10 and a linear increase (p<.05) in serum total protein concentration on week 10 of pigs fed diets supplemented with graded levels of AJE was observed. Faecal lactic acid bacteria counts showed a linear increase (p<.05) on week 5 with the increasing levels of AJE. In conclusion, there existed improvements in growth performance, nutrients digestibility, serum total protein, faecal coliform bacteria and lactic acid bacteria counts and faecal ammonia emission in the finishing pigs fed with AJE-supplemented diet.

Effect of sealing on the feed out face of trench silos on the performance of confined calves

ABSTRACT This study aimed to evaluate the productive performance, dry matter intake, apparent digestibility and ingestive behavior of feedlot calves fed corn silage from the feed out face of trench silos with different types of sealing. The animals were divided into three treatments with four repetitions: Conventional seal - double-sided polyethylene of 110µm thickness; Double-sided seal - double-sided polyethylene of 200µm thickness; and Double seal - composed of double face polyethylene with a thickness of 80µm superimposed on a polyamide translucent vacuum film with a thickness of 20µm. The use of double face sealing provided 12.63% increase in average daily gain and improved food conversion by 0.62 percentage points. The apparent digestibility of the diet with double-face sealing system silage was 4.30% higher than the diet with double-face sealing silage and 11.00% higher than the diet with conventional sealing silage. It is recommended to use the double face sealing with 200µm polyethylene and double face sealing with 80µm thick polyethylene on top of a 20µm thick polyamide translucent vacuum film.

Investigation on Recycling Dry Toilet Generated Blackwater by Anaerobic Digestion: From Energy Recovery to Sanitation

Anaerobic digestion (AD) has been widely adapted for blackwater treatment, however, the effect of water-conserving toilet generated blackwater on the AD process is still unknown. In this study, the anaerobic digestion process of dry toilet generated blackwater was investigated by means of a biomethane potential test. It was demonstrated that anaerobic digestion was inhibited and then adapted because of a high total ammonium nitrogen (TAN) level (3673.3 mg/L). The start-up period was 14.04 days and the biomethane potential of dry toilet blackwater was 402.36 mLCH4/gVS (55 days, 38 °C). Inhabitation and adaptation could be described as the increase of free ammonia nitrogen content and acetic acid concentration, followed by an enhancement of the relative abundance of acetic acid-type methanogens (from 33.53–61.52%). The main pathogen in dry toilet blackwater fermentation broth, Pseudomonas aeruginosa, kept multiplying in the first 8 days and then stabilized at a higher level than that of the beginning. This work showed the self-adjustment process and pathogen dynamics of dry toilet blackwater anaerobic digestion and highlights the significance of dry toilet blackwater characteristics when designing and maintaining anaerobic digestion sanitary treatment and reuse systems.

Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle.

The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry-rolled corn, 20% corn silage, 15% modified wet distillers grains with soluble, and 10% supplement. For each block, total collection of feed, orts, feces, and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction (P > 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect (P = 0.51) on DMI, but RAC had decreased fecal DM output (P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P < 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P < 0.01) than CON. Although treatment did not affect nitrogen intake (P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect (P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea (P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- (n = 9) and RAC-fed (n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split–plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD (P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. The inclusion of RAC in the in vitro substrate increased IVDMD (P < 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter.

Effects of Rumen-Protected Niacin on Dry Matter Intake, Milk Production, Apparent Total Tract Digestibility, and Faecal Bacterial Community in Multiparous Holstein Dairy Cow during the Postpartum Period.

Simple SummaryThe main challenge faced by cows during the first three weeks after calving is the sudden increase in nutrient demand for milk production while dry matter intake and nutrient supply lag. Although metabolic hormone changes are a normal adaptive process in high yielding cows, failure to adapt to this challenge can lead to disease states and affect production and reproductive efficiency. Therefore, a smooth transition from prepartum to postpartum period for optimal dairy cow health and performance. Whether rumen-protected niacin supplementation could be a useful additive was controversial. This work tested whether the widespread use of rumen-protected niacin in multiparous Holstein dairy cows could be justified.Extensive studies about rumen-protected niacin (RPN) supplementation on dairy cows in early-lactation have been done, but the effects of RPN on changes in dry matter intake (DMI), milk production, feed digestibility, and fecal bacterial community were conflicting. The aim of this study was to investigate them affected by RPN in postpartum cows. Multiparous Holstein dairy cows (n = 12, parity = 3.5 ± 0.5, body weights = 740 ± 28 kg) were divided into two groups supplemented with either 0 (CON) or 20 g/d RPN (RPN). Our results showed that RPN supplementation increased DMI and milk production of cows during the first three weeks after calving (p < 0.05). The concentrations of neuropeptide Y and orexin A were significantly higher in RPN group than that in the CON group during postpartum period (p < 0.05). The apparent total-tract digestibility of nutrients was similar between the CON and RPN groups at 2 weeks after calving (p > 0.05). The 16S rRNA gene sequencing analysis showed that RPN had no impact on the alpha and beta diversity, although 4 genera were changed in cow feces at 14 days after calving. Overall, 20 g/d RPN added to the diet could improve DMI and milk yield up to two weeks after calving with little influence on feed digestibility.

Effects of barley and corn as sources of silage and grain on dry matter intake, ruminal fermentation, and total-tract digestibility in growing beef heifers

The objective of this study was to evaluate the use of barley (BS) or corn (CS) silage when fed with dry-rolled barley grain (BG), corn grain (CG), or an equal blend (BCG) of BG and CG for backgrounding cattle. Ruminally cannulated heifers (n = 5) were assigned to an incomplete 6 × 6 Latin square design. Treatments contained either BS or CS in combination with BG, CG, or BCG. Samples were collected to determine dry matter intake, ruminal fermentation, total-tract nutrient digestibility, and nitrogen (N) balance. Interactions between cereal silage and cereal grain sources were detected for the molar proportions of propionate and butyrate where the magnitude of change with the type of cereal grain was increased in heifers fed CS relative to BS. Feeding CS increased estimated microbial N production (silage, P = 0.022) and fecal N excretion (silage, P = 0.042) over BS. Diets containing BG had greater dry matter, organic matter, starch, and gross energy digestibility values compared with CG, but values for BCG were not different (grain, P ≤ 0.043). Based on limited silage × grain interactions, use of CS in backgrounding diets may increase microbial N production relative to BS and dry-rolled CG may reduce apparent total-tract nutrient digestibility relative to dry-rolled BG.