Systematic review and meta-analysis of the methionine utilization efficiency in piglets receiving different methionine sources.

Methionine (Met) is an essential amino acid that can be supplied in different chemical forms: DL-Met, L-Met, and OH-Met. This study aimed (i) to model and compare the utilization efficiency of Met for protein deposition (PD) from all sources and (ii) to determine the efficacy and efficiency of these three free Met sources in average daily gain (ADG) of post-weaning pigs fed at or below the Met requirement. A systematic review of the literature resulted in 1 898 papers being screened for title and abstract, with 24 papers meeting the inclusion criteria. The resulting database containing 208 treatment means was used. Prior to model development, the standardized ileal digestible (SID) Met requirements in percentage in the diet were determined using initial and final BW according to the NRC (2012). Data from piglets fed above the SID Met requirements were excluded from the database prior to statistical analysis. Linear mixed-effects regression models predicting ADG as a function of free Met source and SID methionine intake (Meti) or methionine + cysteine intake (Met + cysi) were used to evaluate the efficacy and efficiency of free Met source for weight gain. Moreover, Met retention was modeled assuming that 16% of ADG is deposited as PD, and that Met accounts for 2% of PD. Met utilization efficiency was calculated as Meti after maintenance divided by Met retained in PD. Met utilization efficiency was 77% for the basal diet, decreased (P < 0.01) as Meti increased, and was equal among the three free Met sources. The mixed-effects models showed no difference in ADG for three free Met sources evaluated (P > 0.05). However, the efficacy (ADG per unit of SID Meti) of free Met sources for weight gain differed between piglets fed L and DL-Met (P < 0.05), while there was no difference (P > 0.05) between piglets fed DL and OH-Met or OH and L-Met. On average, piglets fed L-Met gained 40.3 g/d more weight per unit of increase in SID Meti than those fed DL-Met (model 4; P = 0.05). The efficacy of free Met sources for ADG was also compared using SID Met + cysi as covariable. Piglets fed L- (+11.7 g/d; P = 0.02) or OH-Met (+11.5 g/d; P = 0.04) gained more weight per gram of SID Met + cysi compared to those fed DL-Met. In conclusion, although the efficacy of DL- and L-Met for ADG differed, the efficiency for PD of L-, DL-, and OH-Met were not different in piglets fed at or below Meti requirement.

Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years.

Food production including dairy has been associated with environmental impacts and resource use that has been steadily improving when adjusted per unit of product. The objective of this study was to conduct a cradle-to-farm gate environmental impact analysis and resource inventory of the California dairy production system to estimate the change in greenhouse gas emissions and water and land use over the 50-yr period between 1964 and 2014. Using a life cycle assessment according to international standards and the Food and Agriculture Organization of the United Nations guidelines, we analyzed contributions from dairy production in California to global environmental change. Production of 1 kg of energy- and protein-corrected milk (ECM) in California emitted 1.12 to 1.16 kg of CO2 equivalents (CO2e) in 2014 compared with 2.11 kg of CO2e in 1964, a reduction of 45.0 to 46.9% over the last 50 yr, depending on the model used. Greater reductions in enteric methane intensity (i.e., methane production per kilogram of ECM) were observed (reduction of 54.1 to 55.7%) compared with manure GHG (reduction of 8.73 to 11.9%) in 2014 compared with 1964. This was mainly because manure management in the state relies on lagoons for storage, which has a greater methane conversion factor than solid manure storage. Water use intensity was reduced by 88.1 to 89.9%, with water reductions of 88.7 to 90.5% in crop production, 55.3 to 59.2% in housing and milking, and 52.4 to 54% in free water intake. Improved crop genetics and management have contributed to large efficiencies in water utilization. Land requirements for crop production were reduced by 89.4 to 89.7% in 2014 compared with 1964. This was mainly due to dramatic increases in crop yields in the last 50 yr. The increases in milk production per cow through genetic improvements and better nutrition and animal care have contributed to reductions in greenhouse gas emissions and land and water usage when calculated per unit of production (intensity) basis.

Feedlot efficiency implications on greenhouse gas emissions and sustainability.

The term sustainable has many meanings, but in agriculture it generally refers to some balance between environmental, social, and economic goals. The objective of this project was to quantify inputs and outputs to assess the sustainability implications of 2 feedlot cattle management systems: Never Ever 3 (NE3) and a conventional (CON) system using metabolic modifiers. Angus-cross steers (n=104) were stratified by BW (337 kg ± 17) and randomly assigned to 4 pens per treatment group. The NE3 cattle received no feed additives or implants, whereas CON were implanted with 100 mg of trenbolone acetate and 14 mg of estradiol benzoate on d 1 and 70, and were additionally fed monensin [330 mg/(animal·d)] and tylosin phosphate [90 mg/(animal·d)] in their ration throughout the course of the study, and ractopamine hydrochloride at 254 mg/(animal·d) for the last 29 d on feed. Cattle were shipped on a constant average pen weight basis (596 kg ± 32 BW). The CON cattle had greater ADG (1.81 vs. 1.35 kg, P < 0.01) and were on feed fewer days (146 vs. 188 d, P < 0.01) than the NE3 cattle. No significant differences were observed in HCW (P = 0.072) or dressing percentage (P=0.62) between treatments (P > 0.05); however, CON carcasses averaged larger ribeye area (87 vs. 80 cm(2), P < 0.01), greater Warner-Bratzler shear force measurement (WBSF; 3.46 vs. 3.19 kg, P < 0.01), and smaller USDA marbling score (5.4 vs. 6.2, P < 0.01), and less backfat thickness (1.64 vs. 1.84 cm, P < 0.05) and yield grade (3.38 vs. 3.95, P < 0.01) than NE3 carcasses. Overall, CON cattle consumed 393 kg less DM in the feedlot (1,250 vs. 1,643 kg; P < 0.05). No treatment effects were observed for daily methane (CH(4); P=0.62) or nitrous oxide (N(2)O; P=0.7) emissions per steer. Assuming a constant emission rate on a DMI basis throughout the course of the feedlot trial, CON feedlot management resulted in a 31% decrease in emissions per finished steer compared with NE3 management. Expressing CH(4) emissions on a carbon dioxide equivalent (CO(2)-eq) basis revealed a 1.10-kg CO(2)-eq difference per kilogram BW gain (5.02 kg of NE3 vs. 3.92 kg of CON) between the 2 feedlot management systems. Although the metabolic modifiers resulted in additional costs for the CON treatment group, the cost per kilogram of feedlot BW gain was significantly less ($1.12/kg vs. $1.35/kg; P < 0.05) than NE3. Both production systems satisfied some sustainability criteria, although neither concurrently fulfilled all of the environmental, social, and economic goals of agricultural sustainability.

A model on biological flow of phosphorus in growing pigs / Modelo do fluxo do fósforo em suínos na fase de crescimento

Ten crossbred barrows weighting 20kg were allocated in five groups fed and on diets consisted of different total phosphorus (P) levels: 0.30 percent, 0.40 percent, 0.51 percent, 0.65 percent, and 0.73 percent. The animals were intravenously injected 7.4MBq of radioactive P (32P) and after seven days they were slaughtered for further analysis. The evaluated parameters were intake, excretion, specific activities, and flow of P in compartments (1-gut, 2-blood, 3-bone, and 4-soft tissue). Besides fecal losses, the kidneys played an import role in P regulation. The flows of P from tissue and gut to the blood were affected by P intake.

Foram usados 10 leitões machos castrados com média de peso vivo de 20kg, alojados em gaiolas metabólicas. O delineamento experimental foi inteiramente ao acaso e os tratamentos consistiram em níveis de fósforo (P) nas dietas: 0,30; 0,40; 0,51; 0,65 e 0,73 por cento. Os animais receberam injeção de 7,4 MBq de radiofósforo (32P) e após sete dias foram abatidos para posteriores análises. As variáveis avaliadas foram: ingestão, excreção, atividades específicas e fluxo de P nos compartimentos (1-trato digestivo, 2-corrente sanguínea, 3-tecidos moles e 4-ossos). Além das excreções fecais, os rins também representaram uma rota importante para a excreção do P. O fluxo de P dos tecidos e trato digestivo para o sangue não foi afetado pelo consumo de P. O modelo proposto foi eficiente para avaliar o fluxo de P.

Impairments in pyridoxine-dependent sulphur amino acid metabolism are highly sensitive to the degree of vitamin B6 deficiency and repletion in the pig.

The objectives of the current study included the characterization of the temporal changes in indices of sulphur amino acid metabolism in piglets in response to vitamin B6 deficiency and repletion with graded levels of pyridoxine hydrochloride. In Experiment 1, 12 piglets (average initial weight = 5.3 kg; n = 6 per group) were fed a semi-purified diet containing either 0 (deficiency group) or 3 mg (control group) pyridoxine·HCl/kg diet, using a pair-feeding design, for 6 weeks. Piglets consuming vitamin B6-deficient diets exhibited decreased average daily gains on the 4th week and feed conversion efficiency from the 4th week until the end of the trial (P < 0.05). Plasma pyridoxal-5'-phosphate (PLP), in pigs consuming vitamin B6-deficient diets, was significantly lower than controls throughout the experiment (P < 0.01), reaching a nadir of 14% of the control animals' value by the end of the trial. Indices of sulphur amino acid metabolism, including activities of hepatic cystathionine-ß-synthase (CBS), cystathionine-γ-lyase (CGL) and serine hydroxymethyltransferase, as well as hepatic-free cysteine concentrations were markedly decreased after 6 weeks of B6 deficiency (P < 0.05). Total hepatic mRNA expressions for CBS and CGL were not affected. Concurrently, hepatic-free homocysteine concentrations increased by more than eight-fold (P < 0.01) at the end of the trial. An examination of plasma total homocysteine and cysteine concentrations revealed significant (P < 0.05) differences between treatments, with evidence of an abrupt shift in concentrations at 3 weeks post-initiation of dietary treatments (>25-fold increase in homocysteine; halving of cysteine values). At the end of Experiment 1, vitamin B6 deficiency significantly increased plasma methionine and serine levels, but decreased plasma glycine concentrations (P < 0.05). In Experiment 2, 20 pigs of 14 days old (initial BW = 5.0 kg) were subjected to a 4-week vitamin B6 depletion protocol, based on results obtained in Experiment 1. After the depletion period and assessment of baseline status (four pigs), remaining pigs were allocated to one of four dietary vitamin B6 repletion treatments: 0.75, 1.5, 2.25 and 3 mg/kg diet as pyridoxine·HCl (n = 4 per level) for 14 days. Significant dose-dependent increases in plasma PLP and cysteine, and decreases in homocysteine were observed, and these were sensitive to the duration of repletion. In conclusion, data from the current studies support the use of both plasma PLP and homocysteine as sensitive indices of vitamin B6 status in the pig. Additionally, the observed patterns of responses in vitamin B6-sensitive metabolites are supportive of an inclusion level of 2.25 mg/kg diet, as pyridoxine·HCl, in diets for young pigs.

Technical note: A proposed method to determine the extent of degradation of a feed in the rumen from the degradation profile obtained with the in vitro gas production technique using feces as the inoculum.

A method is proposed to determine the extent of degradation in the rumen involving a two-stage mathematical modeling process. In the first stage, a statistical model shifts (or maps) the gas accumulation profile obtained using a fecal inoculum to a ruminal gas profile. Then, a kinetic model determines the extent of degradation in the rumen from the shifted profile. The kinetic model is presented as a generalized mathematical function, allowing any one of a number of alternative equation forms to be selected. This method might allow the gas production technique to become an approach for determining extent of degradation in the rumen, decreasing the need for surgically modified animals while still maintaining the link with the animal. Further research is needed before the proposed methodology can be used as a standard method across a range of feeds.