Effects of high fibre and low protein diets on performance, digestibility, nitrogen excretion and ammonia emission in the heavy pig

Effects of Lactobacillus-fermented low-protein diets on the growth performance, nitrogen excretion, fecal microbiota and metabolomic profiles of finishing pigs

This study investigated the effects of Lactobacillus-fermented low-protein diet on the growth performance, nitrogen balance, fecal microbiota, and metabolomic profiles of finishing pigs. A total of 90 finishing pigs were assigned to one of three dietary treatments including a normal protein diet (CON) as well as two experimental diets in which a low-protein diet supplemented with 0 (LP) or 1% Lactobacillus-fermented low-protein feed (FLP). In comparison with CON, the LP and FLP significantly increased average daily gain (P = 0.044), significantly decreased feed to gain ratio (P = 0.021), fecal nitrogen (P < 0.01), urine nitrogen (P < 0.01), and total nitrogen (P < 0.01), respectively. The LP group exhibited increased abundances of unclassified_f_Selenomonadaceae, Coprococcus, Faecalibacterium, and Butyricicoccus, while the abundances of Verrucomicrobiae, Verrucomicrobiales, Akkermansiaceae, and Akkermansia were enriched in the FLP group. Low-protein diet-induced metabolic changes were enriched in sesquiterpenoid and triterpenoid biosynthesis and Lactobacillus-fermented low-protein feed-induced metabolic changes were enriched in phenylpropanoid biosynthesis and arginine biosynthesis. Overall, low-protein diet and Lactobacillus-fermented low-protein diet improved the growth performance and reduce nitrogen excretion, possibly via altering the fecal microbiota and metabolites in the finishing pigs. The present study provides novel ideas regarding the application of the low-protein diet and Lactobacillus-fermented low-protein diet in swine production.

Effects of dietary niacinamide and CP concentrations on the nitrogen excretion, growth performance, and meat quality of pigs

Reducing the dietary CP concentration in the formulation of low-protein diets without adverse effects on animal growth performance and meat quality remains challenging. In this study, we investigated the effects of nicotinamide (NAM) on the nitrogen excretion, growth performance, and meat quality of growing-finishing pigs fed low-protein diets. To measure the nitrogen balance, we conducted two trials: in nitrogen balance trial 1, four crossbred (Duroc × Landrace × Large White) barrows (40 ± 0.5 kg BW) were used in a 4 × 4 Latin square design with four diets and periods. The diets consisted of a basal diet + 30 mg/kg NAM (a control dose), basal diet + 90 mg/kg NAM, basal diet + 210 mg/kg NAM, and basal diet + 360 mg/kg NAM. In nitrogen balance trial 2, another four barrows (40 ± 0.5 kg BW) were used in a 4 × 4 Latin square design. The diets consisted of a basal diet + including 30 mg/kg NAM (control), basal diet + 360 mg/kg NAM, low-protein diet + 30 mg/kg NAM, and low-protein diet + 360 mg/kg NAM. To measure growth performance, two trials were conducted. In growth performance trial 1, 40 barrows (37.0 ± 1.0 kg) were randomly allocated to one of four dietary treatments (n = 10 per group), whereas in growth performance trial 2, 300 barrows (41.4 ± 2.0 kg) were randomly allocated to one of four dietary treatments, with each dietary treatment conducted in five repetitions with 15 pigs each. The four diets in the two growth performance trials were similar to those in nitrogen balance trial 2. Supplementing the diet with 210 or 360 mg/kg NAM reduced urinary nitrogen excretion and total nitrogen excretion and increased nitrogen retention comparted with the control diet (P < 0.05). Compared with the control diet, the low-protein diet with 360 mg/kg NAM reduced faecal, urinary, and total nitrogen excretion (P < 0.05) without affecting nitrogen retention and average daily gain (P > 0.05). Pigs fed the low-protein diet with 360 mg/kg NAM showed a decreased intramuscular fat content in the longissimus thoracis muscle when compared with pigs fed the control diet (P > 0.05). Our results suggest NAM as a suitable dietary additive to reduce dietary CP concentration, maximise nitrogen retention and growth performance, and decrease fat deposition in pigs.

Supplementation with Antimicrobial Peptides or a Tannic Acid Can Effectively Replace the Pharmacological Effects of Zinc Oxide in the Early Stages of Weaning Piglets

Zinc oxide (ZnO) harms the environment and can potentially increase the number of drug-resistant bacteria. Therefore, there is an urgent need to find safe and effective alternatives to improve gut health and reduce the incidence of diarrhea in weaned piglets. This study conducted an antibacterial test of ZnO, antibacterial peptides (AMPs), and tannic acid (TA) in vitro. Thirty piglets were randomly allotted to one of the following three dietary treatments: ZnO (2000 mg/kg ZnO diet), AMPs (700 mg/kg AMPs diet), and TA (1000 mg/kg TA diet). The results showed that the minimum inhibitory concentrations of ZnO and TA against Escherichia coli and Salmonella were lower than those of AMPs, and the minimum inhibitory concentrations of ZnO, AMPs, and TA against Staphylococcus aureus were the same. Compared to ZnO, AMPs increased the digestibility of dry, organic matter and the crude fat. Additionally, TA significantly (p < 0.05) increased the digestibility of dry and organic matter. On experimental day 14, the plasma interleukin-6 (IL-6) content of piglets supplemented with AMPs and TA was increased significantly (p < 0.05). On experimental day 28, alanine aminotransferase activity in the plasma of weaned piglets in the ZnO and TA groups was significantly (p < 0.05) higher than in piglets in the AMPs group. The levels of plasma IL-6 and immunoglobulin M (IgM) were significantly higher (p < 0.05) in the ZnO and AMPs groups than in the TA group. On experimental days 14 and 28, no significant differences were observed in the antioxidant capacity among the three experimental groups. Intestinal microbial diversity analysis showed that the Chao1 and ACE indices of piglets in the AMPs group were significantly higher (p < 0.05) than those in the ZnO and TA groups. At the genus level, the relative abundance of Treponema_2 was higher in the feces of piglets fed a diet supplemented with TA than in those fed diet supplemented with ZnO (p < 0.05). The relative abundance of Lachnospiraceae was higher in the feces of piglets fed a diet supplemented with AMPs than in those fed diet supplemented with ZnO or TA. Overall, AMPs and TA could be added to feed as substitutes for ZnO to reduce diarrhea, improve nutrient digestibility and immunity, and increase the abundance of beneficial intestinal bacteria in weaned piglets.

Effects of low protein diet with a balanced amino acid pattern on growth performance, meat quality and cecal microflora of finishing pigs

BACKGROUND

The present study aimed to investigate the effects of low protein diets balanced with four amino acids on growth performance, meat quality and cecal microflora of finishing pigs. Fifty-four healthy hybrid barrows (Duroc × Landrace × Yorkshire) with an average body weight of 70.12 ± 4.03 kg were randomly assigned to one of the three dietary treatments with six replicate pens per treatment (three barrows per pen). The three dietary treatments included a normal protein diet (NP), a low protein diet (LP) and a very low protein diet (VLP).

RESULTS

The average daily gain, average daily feed intake and feed conversion ratio of pigs were not significantly changed with the LP and VLP diets compared to the NP diet (P > 0.05). The water holding capacity and shear force of longissimus dorsi muscle were decreased, whereas the intramuscular fat content of the longissimus dorsi muscle was increased (P < 0.05) in pigs fed with the LP and VLP diets compared to the NP diet. The contents of saturated fatty acids in muscle were decreased (P < 0.05), whereas the content of polyunsaturated fatty acids in muscle was increased (P < 0.01) with the VLP diet compared to the NP diet. The contents of histamine, spermidine, spermine and tyramine of muscle were decreased with the VLP diet compared to the NP diet (P < 0.05). The relative abundance of Turicibacter, Terrisporobacter, Clostridium_sensu_stricto_1 and UCG-005 was higher (P < 0.05), whereas the relative abundance of Lactobacillus and Streptococcus was lower (P < 0.05) in pigs fed with the LP and VLP diets compared to the NP diet. Based on the correlation of cecal microbiota and cecal biogenic amine, the contents of tyramine, spermidine and histamine were negatively correlated with the abundance of Terrisporobacter (P < 0.01) and the content of histamine was positively correlated with the abundance of Lactobacillus (P < 0.01).

CONCLUSION

Balanced with four essential amino acids, the VLP diet with crude protein levels decreased by > 4% increased the intramuscular fat content, changed the fatty acid and amino acid composition of longissimus dorsi muscle and the profile of cecum microbiota, and reduced the content of cecum bioamine, with no negative effect on the growth performance of pigs. © 2022 Society of Chemical Industry.

Comparison of methods for the effective evaluation of the energy content of poultry byproduct meal for beagles

The objectives of this study were to compare the energy values of poultry byproduct meal (PBM) as feed for adult beagle dogs using the direct, difference, and regression methods to examine dogs' nitrogen metabolism, energy utilization, gaseous metabolism, and body health. Five groups of six 12 mo old female beagles with an average body weight of 9.67 ± 0.52 kg were tested in a 5 × 6 incomplete Latin square design, with six repetitions in each group. Five experimental diets were tested consisting of 100% PBM; three substitution diets containing either 15%, 30%, or 45% PBM (termed 15PBM, 30PBM, and 45PBM, respectively); and a basal diet (included 6.90% PBM). Each experimental period lasted for 10 d, comprising 4 d of dietary acclimation followed by 6 d of testing (including 3 d feeding period and 3 d fasting period), during which the heat production (HP) was determined and feces and urine were collected. Results showed that, in the feeding state, the nitrogen intake, urinary nitrogen, apparent nitrogen digestibility, retained nitrogen, andHP increased significantly (P < 0.05) as the PBM level increased. The net protein utilization, biological value of protein, and total apparent digestibility of amino acids did not differ between the 30PBM and 45PBM diets (P > 0.05). The O2 consumption and CO2 production of beagles during the fasting period were not influenced by the PBM level (P > 0.05). The digestible energy and metabolizable energy values of the PBM estimated by the regression method were 20.16 and 18.18 MJ/kg dry matter (DM), respectively, and did not differ from those determined by the direct method (P > 0.05). The fecal DM percentages and fecal PBM scores were significantly higher in the PBM diet than in the difference method groups (P < 0.05). The direct method group had a significantly higher fecal score (4.63) than the other groups (P < 0.05), The fecal score of the 45PBM diet (3.50) was significantly higher than the 30PBM diet (2.90; P < 0.05). In summary, the direct and difference methods of determining the effective energy value of PBM for beagles, produce significantly different results. Under the conditions of this test, the best proportion of PBM in beagle feed for optimum energy provision is 30%.

Swine diets: Impact of carbohydrate sources on manure characteristics and gas emissions

Swine growers seeking to lower costs and environmental impact have turned to alternative carbohydrate feed sources. A feeding trial was conducted to determine the effect carbohydrate sources have on manure composition and gas emissions. A total of 48 gilts averaging 138 kg BW were fed diets consisting of (a) low fiber (LF) grain, or (b) high fiber (HF) aro-industrial co-product (AICP). The LF diets included corn and soybean meal (CSBM) and barley soybean meal (BSBM). The HF AICP diets were CSBM based and supplemented with one of the following materials: beet pulp; corn distillers dried grains with solubles; soybean hulls; or wheat bran. Diets were fed for 42 d with an average daily feed intake of 2.71 kg d-1. Feces and urine were collected twice daily and added to manure storage containers in which manure slurries were monitored for gas emissions and chemical properties. Manures of animals fed HF diets had significantly (P < 0.05) more excretion of solids, C, N, and organic N, but less total S compared to pigs fed the LF diets. Animals feed HF diets had significantly (P < 0.05) higher levels of ammonia, sulfide, volatile fatty acids, and phenols in manure compared to pigs fed the LF diets. Manure of animals fed HF diets had 30% (P < 0.05) lower NH3 and 17% lower hydrogen sulfide emissions; however, fiber had no impact on odor emissions. Based on the partitioning of nutrients, animals fed HF fiber diets had increased manure retention for C and N but decreased levels of N gas emissions and manure S. There were little differences in manure and gas emissions for animals fed LF diets, but the source of HF AICP diets had a significant impact on manure composition and gas emissions.

Impact of Rearing Strategies on the Metabolizable Energy and SID Lysine Partitioning in Pigs Growing from 90 to 200 kg in Body Weight

The current nutrient recommendations focus on pigs fed ad libitum up to 140 kg in body weight (BW). It remains unclear whether this applies to pigs weighing above 140 kg in BW under different rearing conditions. This study aimed to estimate protein (Pd) and lipid (Ld) depositions and the metabolizable energy (ME), standardized ileal digestible lysine (SID lysine) requirement and partitioning in 224 C21 Goland pigs (90−200 kg in BW). The control pigs (C) received diets limiting ME up to 170 kg in slaughter weight (SW) at 9 months of age (SA); older (OA) pigs had restricted diets limiting ME and SID lysine up to 170 kg in SW at >9 months SA; younger (YA) pigs were fed nonlimited amounts of ME and SID lysine up to 170 kg in SW at <9 months SA; and greater weight (GW) pigs were fed as the YA group, with 9 months SA at >170 kg in SW. The estimated MEm averaged 1.03 MJ/kg0.60. An 11% increase in MEm was observed in OA pigs compared to the controls. Energy restriction had negligible effects on the estimated MEm. The marginal efficiency of SID lysine utilization for Pd averaged 0.725, corresponding to a SID lysine requirement of 9.8 g/100 g Pd.

Emissions of Gaseous Pollutants from Pig Farms and Methods for their Reduction – A Review

Agriculture contributes significantly to anthropogenic emissions of greenhouse gases (GHG). Livestock production, including pig production, is associated with several gaseous pollutants released into the atmosphere, including carbon dioxide (CO2), methane (CH4), ammonia (NH3) and nitrous oxide (N2O). Emissions of volatile organic compounds (VOCs), including alcohols, aldehydes, and aromatic and aliphatic hydrocarbons, as well as typically odorous pollutants, are an inseparable element of raising and breeding farm animals. These emissions can degrade local and regional air quality, contribute to surface water eutrophication and acid rain, and increase the greenhouse gas footprint of the production sector. The paper is organized as follows. First, the sources and factors influencing the level of emissions from pig houses are described. Next, the effects of dietary methods (optimization of animal diets), hygienic methods (including microclimate optimization) and technological methods (application of technological solutions) for mitigating emissions from pigs are discussed.

Altering Dietary Soluble Protein Levels With Decreasing Crude Protein May Be a Potential Strategy to Improve Nitrogen Efficiency in Hu Sheep Based on Rumen Microbiome and Metabolomics

Ruminants account for a relatively large share of global nitrogen (N) emissions. It has been reported that nutrition control and precise feeding can improve the N efficiency of ruminants. The objective of the study was to determine the effects of soluble protein (SP) levels in low-protein diets on growth performance, nutrient digestibility, rumen microbiota, and metabolites, as well as their associations of N metabolism in fattening Hu sheep. Approximately 6-month-old, 32 healthy fattening male Hu sheep with similar genetic merit and an initial body weight of 40.37 ± 1.18 kg were selected, and divided into four groups (n = 8) using the following completely randomized design: the control diet (CON) with a 16.7% crude protein (CP) content was prepared to meet the nutritional requirements of fattening sheep [body weight (BW): 40 kg, average daily gain (ADG): 200–250 g/d] according to the NRC recommendations; other three include low protein diets (LPA, LPB, and LPC) of CP decreased by ~10%, with SP proportion (%CP) of 21.2, 25.9, and 29.4 respectively. The feeding trial lasted for 5 weeks including the first week of adaptation. The results showed no difference in the growth performance (P > 0.05); DM and CP digestibility were higher in LPB and LPC, with maximum organic matter digestibility in LPB (P < 0.05). Low-protein diets decreased serum urea-N whereas urinary urea-N was lower in LPB and LPC (P < 0.05), while N retention and the biological value of N were higher in LPB and LPC (P < 0.05). Ruminal NH₃-N concentration in LPA and LPB was low than CON (P < 0.05), while total volatile fatty acid (TVFA), acetate, propionate, and butanoate were all lowest in LPA (P < 0.05). In the rumen microbiome, LPB increased the community richness in Prevotellaceae and Prevotella_1 (P < 0.05); Metabolomics analysis revealed low-protein diets downregulated the amino acid metabolism pathways, while the biosynthesis of unsaturated fatty acids along with vitamin B6 metabolism were upregulated with increased SP. These findings could help us understand the role of different SP levels in the regulation of rumen microbial metabolism and N efficiency. Overall, low-protein diets (CP decreased by ~10%) can reduce serum urea-N and ruminal NH₃-N without affecting the growth performance of fattening Hu sheep. Additionally higher N efficiency was obtained with an SP proportion of ~25–30%.

Influence of Slaughter Weight and Sex on Growth Performance, Carcass Characteristics and Ham Traits of Heavy Pigs Fed Ad-Libitum

Simple Summary

In recent years, pigs involved in the dry-cured ham production system have suffered from excessive leanness. This has led to the increase of slaughter weight (SW) to achieve greater carcass and ham fatness statuses to compensate for the loss in dry-curing aptitude. The production guidelines for the production of Italian dry-cured ham are currently under revision and an extension of the range of carcass weights from 126 to 168 kg, corresponding to about 146 to 210 kg of SW, has been proposed. However, little is known about the influence of SW in the range of 140–200 kg on growth performance, feed efficiency, carcass quality and ham curing aptitude. We hypothesized that an increased SW could exert a positive influence on ham characteristics. Data from 159 pigs fed ad libitum with diets, unlimiting for nutrient contents, up to 8 or 9 months of age (140–200 kg SW) were used. Greater SWs were linearly and positively associated with the growth performance of the pigs and with better ham quality traits. Greater SW increased ham weight, muscularity, and greater fat covering, according to the dry-cured ham industry’s expectations. Barrows produced hams with greater weight and marbling than gilts.

Abstract

Slaughter weight (SW) is critical for dry-cured ham production systems with heavy pigs. A total of 159 C21 Goland pigs (gilts and barrows) at 95 ± 9.0 kg body weight (BW) from three batches were used to investigate the impact of ad libitum feeding on SW, growth performance, feed efficiency, and carcass and green ham characteristics. Diets contained 10 MJ/kg of net energy and 7.4 and 6.0 g/kg of SID-lysine. Slaughter weight classes (SWC) included <165, 165–180, 180–110 and >210 kg BW. In each batch, pigs were sacrificed at 230 or 258 d of age. Left hams were scored for round shape, fat cover thickness, marbling, lean colour, bicolour and veining. Data were analyzed with a model considering SWC, sex and SWC × Sex interactions as fixed factors and the batch as a random factor. The linear, quadratic and cubic effects of SWC were tested, but only linear effects were found. Results showed that pigs with greater SWC had greater average daily gain and feed consumption, with similar feed efficiency and better ham quality traits: greater ham weight, muscularity, and fat coveringin correspondence of semimembranosus muscle. Barrows were heavier and produced hams with slightly better characteristics than gilts.

Nitrogen balance in slow-growing Windsnyer pigs fed on incremental levels of amarula (Sclerocarya birrea subsp. caffra) nut cake

Feeding-derived amarula cake to growing pigs can overcome a narrow range of ingredients challenges and improve productivity. The objective of the current study was to determine the response in nitrogen (N) balance in slow-growing pigs fed on incremental levels of amarula nut cake (ANC). Thirty clinically healthy male growing Windsnyer (30.7 kg ± 6.57) (mean ± standard deviation) were individually assigned to separate pens in a completely randomized design, with six pigs per dietary treatment. Iso-energetic experimental diets were formulated to contain 0, 50, 100, 150, and 200 g/kg dry matter (DM) of ANC using the summit and dilution technique. Pigs were given 10 days of dietary adaptation and a collection period of 5 consecutive days after 31 days of feeding. Nitrogen intake increased linearly with incremental levels of ANC (P < 0.01). As ANC inclusion increased, the nitrogen (N) absorption, apparent N digestibility, and N retention in pigs increased until it reached a maximum, then started to decrease (P < 0.05). Nitrogen utilization increased at the rate of 0.63 g for each 1 g increase in ANC (P < 0.01). There was a linear decrease (P < 0.01) in total nitrogen excretion through urine and faeces with ANC inclusion. Urinary pH levels decreased quadratically in response to graded levels of ANC (P < 0.01). The relationship between urinary pH and ANC inclusion was Y = 0.0115x² - 0.3491x + 4.872 (P < 0.01). The nitrogen balance responses were due to ANC inclusion in diets that were balanced for limiting amino acids. It can be concluded that ANC reduces N excretion, potentially minimizing ammonia volatilization, which makes it an alternative protein source for slow-growing pigs.

Free-Range and Low-Protein Concentrated Diets in Iberian Pigs: Effect on Plasma Insulin and Leptin Concentration, Lipogenic Enzyme Activity, and Fatty Acid Composition of Adipose Tissue

Simple Summary

Recently, it has been shown that reducing dietary crude-protein levels during the final fattening period prior to slaughter is a suitable strategy to increase intramuscular fat content in Iberian pig meat, without affecting pig growth. Investigating the effect of a low-protein diet on the metabolism, development, and composition of the adipose tissue of Iberian pigs, and the obese porcine breed, was the objective of this study. Three groups of pigs fed under free-range conditions and in confinement with concentrated diets with low- and standard-protein contents were studied. All three groups exhibited the same backfat thickness at the end of the fattening period. The level of hormones and activities of enzymes related to adipogenic metabolism were affected by diet, with differences between free-range and intensive feeding systems. Therefore, we suggest that feeding Iberian pigs on low-protein diets did not result in fatter carcasses, and is thus a useful strategy to improve Iberian pig meat quality.

Abstract

The purpose of this study was to investigate the effect of diets with different protein contents on carcass traits, plasma hormone concentration, lipogenic enzyme activities, and fatty acid (FA) composition in the adipose tissue of Iberian pigs. Twenty-four castrated male Iberian pigs (eight per feeding diet) were fed under free-range conditions with acorns and grass (FR), and in confinement with concentrated diets with standard (SP) and low-protein contents (LP) from 116.0 to 174.2 kg live weight. Backfat thickness was not affected by diet. The plasma leptin concentration was higher (p < 0.001) in the FR group than in the LP and SP groups, while insulin concentration was higher in the SP group than in the LP and FR groups. The lipogenic enzyme activities of glucose-6-phosphate dehydrogenase, malic enzyme, and glycerol-3-phosphate dehydrogenase were lower in the FR group compared to the LP and SP pigs. The activities of these enzymes were adipose-tissue-specific. No differences were found in FA composition of adipose tissue between the SP and LP groups, while the FR pigs had lower proportions of saturated FA and higher proportions of monounsaturated and polyunsaturated FA than the SP and LP pigs. In conclusion, feeding low-protein diets in Iberian pigs does not seem to affect adipose carcass traits, strengthening previous findings that indicate that this is a good strategy to improve meat and dry-cured product quality.

Effects of different levels of crude protein and protease on nitrogen utilization, nutrient digestibility, and growth performance in growing pigs

This study was conducted to evaluate the effects of different levels of crude protein (CP) and protease on nitrogen (N) utilization, nutrient digestibility, and growth performance in growing pigs. A total of six crossbred ([Landrace × Yorkshire] × Duroc) barrows were individually accepted in 1.2 m × 0.7 m × 0.96 m stainless steel metabolism cages. The pigs (average initial body weight of 27.91 ± 1.84 kg) randomly assigned to six diets with six weeks (6 × 6 Latin square design). The experiment was carried out in an environment with a temperature of 23 ± 1.5°C, a relative humidity of 83 ± 2.3% and a wind speed of 0.25 ± 0.03 m/s. The dietary treatments were arranged in a 2 × 3 factorial design with two levels of CP (15.3% or 17.1%) and three levels of protease (0 ppm, 150 ppm, or 300 ppm). The average daily gain and gain to feed ratio (G:F) tended to increase (p = 0.074) with increasing amounts of protease. The low CP level diet reduced (p < 0.050) urinary and fecal N concentrations, the total N excretion in feces, and increased (p < 0.050) N retention. Different protease levels in the diet did not affect (p > 0.05) at N intake, but supplementation of the diets with 300 ppm protease decreased (p < 0.050) the N concentration in urine and feces and tended to increase (p = 0.061) the percentage of N retention retained of the total N intake. The dietary CP level did not affect (p > 0.050) the apparent total tract digestibility (ATTD) of dry matter, digestible energy (DE), and metabolic energy (ME), but diet supplementation with 300 ppm protease showed higher (p < 0.050) ATTD of DE and ME than in the protease-free diet. Therefore, a low protein diet with protease could improve the utilization of nitrogen, thereby reducing the negative effect of N excretion into the environment while maintaining or increasing growth performance compared to a high protein diet.

The Impact of Producing Type and Dietary Crude Protein on Animal Performances and Microbiota Together with Greenhouse Gases Emissions in Growing Pigs

Simple Summary

To study the effect of dietary crude protein (CP) restriction in two different pig producing types and the role of gut microbiota, 32 pure castrated male Duroc and 32 entire male hybrid (F2) piglets were raised in a three-phase feeding regime with a restriction in CP content of the diets. The average body weight of hybrid animals were higher compared to Duroc pigs. No changes were found in average daily feed intake (ADFI) of hybrid animals in comparison to Duroc pigs. Hybrid animals apparently digested more CP than Duroc and Duroc pigs emitted more CH₄ and ammonia with respect to the hybrids. Dietary protein restriction did not alter emissions of contaminant gases nor microbial community structure in terms of diversity, although some genera were affected by the dietary challenge.

Abstract

In order to reduce dietary nitrogen and achieve an efficient protein deposition as well as decrease N wastage, we challenged the nutrient utilization efficiency of two different producing types in front of a dietary crude protein (CP) restriction and studied the role of the microbiota in such an adaptation process. Therefore, 32 pure castrated male Duroc (DU) and 32 entire male hybrid (F2) piglets were raised in a three-phase feeding regime. At each phase, two iso caloric diets differing in CP content, also known as normal protein (NP) and low protein (LP), were fed to the animals. LP diets had a fixed restriction (2%) in CP content in regards to NP ones throughout the phases of the experiment. At the end of third phase, fecal samples were collected for microbiota analysis purposes and greenhouse gases emissions, together with ammonia, were tested. No changes were found in average daily feed intake (ADFI) of animals of two producing types (Duroc vs. F2) or those consumed different experimental diets (NP vs. LP) throughout the course of study. However, at the end of each experimental phase the average body weight (BW) of hybrid animals were higher compared to Duroc pigs, whereas a reverse trend was observed for average daily gain (ADG), where Duroc pigs showed greater values with respect to hybrid ones. Despite, greater CH₄ and ammonia emissions in Duroc pigs with respect to F2, no significant differences were found in contaminant gases emissions between diets. Moreover, LP diets did not alter the microbial community structure, in terms of diversity, although some genera were affected by the dietary challenge. Results suggest that the impact of reducing 2% of CP content was limited for reduction in contaminant gases emissions and highlight the hypothesis that moderate change in the dietary protein levels can be overcome by long-term adaptation of the gut microbiota. Overall, the influence of the producing type on performance and digestive microbiota composition was more pronounced than the dietary effect. However, both producing types responded differently to CP restriction. The use of fecal microbiota as biomarker for predicting feed efficiency has a great potential that should be completed with robust predictive models to achieve consistent and valid results.

Effects of dietary crude protein level and N-carbamylglutamate supplementation on nutrient digestibility and digestive enzyme activity of jejunum in growing pigs

Three experiments were conducted to investigate the effects of dietary crude protein (CP) level and N-carbamylglutamate (NCG) supplementation on apparent total tract digestibility (ATTD) and ileal digestibility of nutrients and digestive enzyme activity of jejunum in growing pigs. In experiment 1, 10 Duroc × Landrace × Yorkshire barrows (initial BW: 48.7 kg) were allotted to a three-period switchback design with five experimental diets and two replicate pigs per diet in each period. Diets were categorized as high CP (HP, 18% CP), moderate low CP (MLP, 15% CP), very low CP (VLP, 12% CP), and MLP and VLP with 0.1% NCG supplementation. Feces and urine were collected from day 6 to day 11 after a 5-d adaptation period. The DE, ME, and ATTD of GE, OM, CP, NDF, ADF, and P decreased (P < 0.01) with a reduction of dietary CP, but no effect of dietary treatments on pig daily N retention was detected. The NCG supplementation increased (P < 0.01) DE and ATTD of ADF of the VLP diet. In experiment 2, 10 jejunal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 44.5 kg) were fed five diets for three periods as experiment 1. Jejunal fluid was collected on days 6 and 8 after a 5-d adaptation period. The digestive enzymes activity was not affected by dietary CP level, except for α-amylase, for which there was a decrease (P < 0.01) in pigs fed VLP diets compared to HP and MLP diets. In experiment 3, 12 ileal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 46.7 kg) were allotted to a three-period switchback design with six diets and two replicate pigs per diet in each period. The six experimental diets consisted of five experimental diets as experiment 1 and one N-free diet. Ileal digesta was collected from day 6 to day 8 after a 5-d adaptation period. Results indicated that apparent ileal digestibility (AID) of CP and P and ileal digestibility of Arg, His, Ile, Leu, Phe, and all dispensable AA, except Pro, decreased (P < 0.01) in pigs fed VLP diet compared to HP and MLP diets, but AID of GE, OM, EE, NDF, and ADF were not affected. The supplementation of NCG in the VLP diet increased (P < 0.01) the AID of CP and ileal digestibility of Arg, His, Leu, Phe, Val, Ser, and Tyr. In conclusion, reducing dietary CP level decreased nutrient digestibility, but improved the efficiency of dietary N utilization and reduced N emission. Moderate reduction of dietary CP level had a minimal effect on nutrient digestibility and digestive enzyme activity. Additionally, NCG supplementation plays a beneficial effect on nutrient digestion only if the dietary CP level is extremely lowered.

Effects of adding sodium dichloroacetate to low-protein diets on nitrogen balance and amino acid metabolism in the portal-drained viscera and liver of pigs

Background

Identifying regulatory measures to promote glucose oxidative metabolism while simultaneously reducing amino acid oxidative metabolism is one of the foremost challenges in formulating low-protein (LP) diets designed to reduce the excretion of nitrogen-containing substances known to be potential pollutants. In this study, we investigated the effects of adding sodium dichloroacetate (DCA) to a LP diet on nitrogen balance and amino acid metabolism in the portal-drained viscera (PDV) and liver of pigs.To measure nitrogen balance, 18 barrows (40 ± 1.0 kg) were fed one of three diets (n = 6 per group): 18% crude protein (CP, control), 13.5% CP (LP), and 13.5% CP + 100 mg DCA/kg dry matter (LP-DCA). To measure amino acid metabolism in the PDV and liver, 15 barrows (40 ± 1.0 kg) were randomly assigned to one of the three diets (n = 5 per group). Four essential amino acids (Lys, Met, Thr, and Trp) were added to the LP diets such that these had amino acid levels comparable to those of the control diet.

Results

The LP-DCA diet reduced nitrogen excretion in pigs relative to that of pigs fed the control diet (P < 0.05), without any negative effects on nitrogen retention (P > 0.05). There were no differences between the control and LP-DCA groups with respect to amino acid supply to the liver and extra-hepatic tissues in pigs (P > 0.05). The net release of ammonia into the portal vein and production rate of urea in the liver of pigs fed the LP-DCA diet was reduced relative to that of pigs fed the control and LP diets (P < 0.05).

Conclusion

The results indicated that addition of DCA to a LP diet can efficiently reduce nitrogen excretion in pigs and maximize the supply of amino acids to the liver and extra-hepatic tissues.

Validation of a New Resource-Efficient Feeding System for Fattening Pigs Using Increased Crude Fiber Concentrations in Diets: Feed Intake and Ammonia Emissions

Simple Summary

The feeding of fattening pigs and its associated ammonia emissions are current core problems in social debate that affects climate change and sustainability. Feeding methods offer great potential to increase animal welfare and sustainability, and negative impacts on the environment can be reduced. Fattening pigs differ in their performance potential and in their nutrient requirements. A high feed intake capacity can lead to luxury consumption. Diets rich in crude fiber should prevent excess feed intake and cause better nitrogen fixation by microorganisms in the animals’ large intestines. In a pig fattening farm, it was investigated whether and how diets rich in crude fiber can influence feed intake and ammonia emissions. The animals were divided into feeding groups according to their presumed performance potential by ultrasound examinations. Therein, body compositions were evaluated, and feed intake capacity and body weight were automatically recorded. The aim of the study was to enable adapted feeding of the animals by regarding their individual differences in body composition and performance potential. Roughage-based diets had significant influence on feed intake and did not increase ammonia emissions. Based on the results of this study a performance-based control of the feed intake should be made possible.

Abstract

The housing of fattening pigs, their feeding, and the emissions associated with this process are subjects of criticism. In order to reduce emissions and ensure resource efficiency, new paths must be taken; animals must be fed closer to their actual needs. In a pig fattening farm, 655 animals were grouped according their body weight and their body composition, consisting of weight and muscle-fat-ratio, which was determined by ultrasound examinations. The influence of different concentrations of triticale whole plant silage (WPS) (from 2.5% to 10%) on the feed intake capacity (3.88 kg to 2.71 kg (88% dry matter (DM))) of each group and the ability to control it was determined. Ammonia emissions were measured and the pens floor pollution was assessed. The animals could be distinguished significantly from each other by ultrasound examinations. The crude fiber influenced the level of daily feed intake. Ammonia emissions were not negatively influenced and could be partly reduced. There was no negative impact on surface contamination due to the increased use of crude fiber. The amount of daily feed intake was controlled by crude fiber rich diets. If these findings are adapted to certain types of pigs, a reduction of emissions and an increased resource efficiency can be expected.

Effect of Free-Range and Low-Protein Concentrated Diets on Growth Performance, Carcass Traits, and Meat Composition of Iberian Pig

Simple Summary

It is generally assumed in the Iberian pig sector that substitution of traditional free-range rearing, with acorns and grass, by mixed diets affects intramuscular fat content and fatty-acid composition, among others, causing a decrease in meat quality. As mixed diets are usually formulated with higher protein contents than those supplied by natural resources consumed by Iberian pig fed extensively, we hypothesized that the use of a low-protein diet in the final fattening period of pig could be a suitable strategy to improve meat and dry-cured product quality. However, it is also necessary to evaluate the effect of this strategy on performance and carcass traits of pigs. In this study, we found that Iberian pigs fed on low-protein diets had higher intramuscular fat content and different meat composition compared to pigs fed on concentrates with standard protein levels, which could be a suitable way of improving the Iberian pig meat and dry-cured product quality.

Abstract

The feeding system is one of the main factors influencing the Iberian pig meat quality. This experiment was undertaken to evaluate the influence of feeding diets containing different levels of protein on performance, carcass, and meat quality of Iberian pigs. To that aim, 24 castrated male Retinto Iberian pigs with an average weight of 116 kg were fed under free-range conditions with acorns and grass (FR), and on concentrated diets in confinement with standard (SP) and low protein content (LP). The crude protein content in acorns was lower than that in the grass and SP diet, but similar to that in the LP diet. FR pigs needed more time to achieve slaughter weight than LP and SP pigs. Iberian pigs fed on low-protein diet (FR and LP) had a higher intramuscular fat content in the musculus serratus ventralis than SP pigs. The influence of diet on the fatty-acid composition was reflected more markedly in subcutaneous fat than in muscles. FR pigs showed a higher level of C18:1 n-9 and total polyunsaturated fatty acids and lower total saturated fatty acids in subcutaneous fat than LP and SP. It is concluded that diets with low protein levels do not affect Iberian pig productive traits but change the meat composition, rendering them an interesting strategy to improve the quality of Iberian pig meat and dry-cured products.

Effects of different levels of dietary protein with or without plant extract YGF251 on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding, and fecal gas emission in growing pigs

This experiment was conducted to evaluate the effects of plant extract YGF251 supplementation in different protein level diets on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding, and fecal gas emission in growing pigs. A total of 144 pigs (24.72 ± 1.54 kg) were randomly assigned to the treatments in a 2 × 3 factorial arrangement of dietary protein levels (15.50%, 14.00% or 12.50%) and plant extract YGF251 levels (0 or 0.05%) with 6 replications per treatment and 4 pigs per pen. Pigs fed low protein diets had reduced average daily gain (p < 0.05) and increased feed conversion ratio (p < 0.01) compared with pigs fed high protein diets. The apparent total tract digestibility of nitrogen was decreased (p < 0.05) when reducing dietary protein level. Fecal ammonia and hydrogen sulfide emissions were reduced (p < 0.05) when reducing dietary protein level. In conclusion, the results of the current study indicated that reducing dietary protein level impaired growth performance and nitrogen digestibility but reduced ammonia and hydrogen sulfide emissions in growing pigs. Dietary supplementation with 0.05% herbal extract YGF251 was not effective in improving growth performance, nutrient digestibility, or in decreasing gas emission in different protein diets.

Effect of fibrous diets on chemical composition and odours from pig slurry

OBJECTIVE

Incorporating high fibre ingredients into pig diets has the potential to reduce odour emissions from of pigs. The current study was carried out to determine effect of diets containing 0, 80 and 160 g/kg of each of lucerne hay, maize cobs and sunflower husks on the chemical characteristics and odours from pig slurries.

METHODS

Twenty eight pigs averaging 18±2.0 kg were kept in individual cages, over four weeks. All pigs were fed ad libitum. Faeces and urine were collected, mixed in a 1:2.3 ratio (w/w), stored and fermented for 16 days in a temperature controlled room at 22°C±2.3°C. The slurry was sampled twice (on day 1 and on day 16) of the fermentation period and analysed for pH, chemical oxygen demand (COD), nitrogen and short chain fatty acids (SCFA) concentration, on wet basis. All samples were tested for odour offensiveness using 18 panelists. A scale of 1 to 5 was used to rank the odour severity, (1 = not offensive, 5 = extremely offensive).

RESULTS

Slurry pH and COD varied with fibre source (p<0.05). On day 16, COD for lucerne hay, sunflower husk and maize cobs were 369, 512, and 425 (standard error of the mean = 34.2) mg of oxygen per litre. Total SCFA concentration was higher at day 16 than day 1 (p< 0.05). Odour offensiveness varied with fibre source across both incubation periods (p<0.05). Sunflower husks and lucerne hay-based diets were rated as less offensive (mean rank = 2.2) than maize cob diets (mean rank of 4.3) (p<0.05).

CONCLUSION

It was concluded that different fibre sources and incubation period influence chemical composition and odour of the slurry. There is, thereby, a need to incorporate locally available fibrous feeds in the diet of pigs because they have an economical and environmental relevance to pig management.

Low-Protein Diets Decrease Porcine Nitrogen Excretion but with Restrictive Effects on Amino Acid Utilization

Reducing dietary crude protein (CP) intake effectively decreases nitrogen excretion in growing-finishing pigs but at the expense of poor growth when dietary CP content is reduced by ≥3%. In this study, we investigated the main disadvantages of low-protein diets supplemented with lysine, methionine, threonine, and tryptophan in pigs. First, changes in the nitrogen balance in response to differences in dietary CP content (18%, 15%, and 13.5%) were investigated in barrows (40 kg). Then, barrows (40 kg) surgically fitted with catheters in the mesenteric vein, portal vein, hepatic vein, and carotid artery were used to investigate changes in amino acid (AA) metabolism in the portal-drained viscera and liver in response to differences in dietary CP content. The results showed that low-protein diets reduced fecal and urinary nitrogen excretion ( P < 0.05) meanwhile resulted in significant decreases in nitrogen retention ( P < 0.05). Moreover, a reduction in the dietary CP content from 18% to 13.5% resulted in decreases in the net portal fluxes of NH₃, glycine, and alanine as well as in the urea production in the liver ( P < 0.05), whereas their values as a percentage of nitrogen intake did not decline ( P > 0.05). The net portal fluxes of nonessential AA (NEAA) were reduced in the low-protein diet groups ( P < 0.05), while essential AA consumption in the liver increased ( P < 0.05). Thus, low-protein diets result in reductions in both nitrogen excretion and retention, and NEAA deficiency may be a major disadvantage of low-protein diets.

Advances in low-protein diets for swine

Recent years have witnessed the great advantages of reducing dietary crude protein (CP) with free amino acids (AA) supplementation for sustainable swine industry, including saving protein ingredients, reducing nitrogen excretion, feed costs and the risk of gut disorders without impairing growth performance compared to traditional diets. However, a tendency toward increased fatness is a matter of concern when pigs are fed low-protein (LP) diets. In response, the use of the net energy system and balanced AA for formulation of LP diets has been proposed as a solution. Moreover, the extent to which dietary CP can be reduced is complicated. Meanwhile, the requirements for the first five limiting AA (lysine, threonine, sulfur-containing AA, tryptophan, and valine) that growing-finishing pigs fed LP diets were higher than pigs fed traditional diets, because the need for nitrogen for endogenous synthesis of non-essential AA to support protein synthesis may be increased when dietary CP is lowered. Overall, to address these concerns and give a better understanding of this nutritional strategy, this paper reviews recent advances in the study of LP diets for swine and provides some insights into future research directions.

Blood parameters in fattening pigs from two genetic types fed diet with three different protein concentrations

The study aimed to evaluate possible differences between two genetic groups (GG) of pigs, fed diets varying in dietary CP level, in hematological and biochemical plasma profiles. The study was carried out in an experimental farm and involved 36 barrows (average BW 129 ± 11 kg) from two GG: group A (18 Italian Duroc boars × Italian Large White sows) and group D (18 DanBred Duroc), fed three experimental diets: a conventional diet and two low-protein diets (LP1 and LP2). A digestibility/balances trial was carried out on 12 pigs A and 12 pigs D that were housed individually in metabolic cages during four digestibility/balances periods. The experimental design was a factorial design, with 3 diets × 2 GG × 4 periods. The experiment lasted 56 d. Blood was sampled from jugular vein in the morning before feed distribution from all barrows in pens at the start and the end of the experimental period; a supplementary blood sample was collected from the 24 pigs at the end of the four digestibility periods (six pigs per period). Blood was analyzed for hematological and biochemical parameters and serum protein profile using automated analyzers. The GG D showed lower white blood cells (WBC), lymphocyte, and monocyte counts than A group. The GG affected several plasma metabolite concentrations: triglycerides, creatinine, Cl, Fe, alkaline phosphatase, and tartrate-resistant acid phosphatase activities were higher in D groups, while urea, albumin, Ca, Na, total bilirubin, and albumin as percentage of total protein were lower than A group. On the contrary, the dietary protein level neither affects WBC nor their populations; only a trend was reported for erythrocytes (red blood cell) and platelets. The diet affected only plasma urea and total bilirubin concentrations.

Greenhouse Gas and Ammonia Emissions from Different Stages of Liquid Manure Management Chains: Abatement Options and Emission Interactions

Farm livestock manure is an important source of ammonia and greenhouse gases. Concerns over the environmental impact of emissions from manure management have resulted in research efforts focusing on emission abatement. However, questions regarding the successful abatement of manure-related emissions remain. This study uses a meta-analytical approach comprising 89 peer-reviewed studies to quantify emission reduction potentials of abatement options for liquid manure management chains from cattle and pigs. Analyses of emission reductions highlight the importance of accounting for interactions between emissions. Only three out of the eight abatement options considered (frequent removal of manure, anaerobic digesters, and manure acidification) reduced ammonia (3-60%), nitrous oxide (21-55%), and methane (29-74%) emissions simultaneously, whereas in all other cases, tradeoffs were identified. The results demonstrate that a shift from single-stage emission abatement options towards a whole-chain perspective is vital in reducing overall emissions along the manure management chain. The study also identifies some key elements like proper clustering, reporting of influencing factors, and explicitly describing assumptions associated with abatement options that can reduce variability in emission reduction estimates. Prioritization of abatement options according to their functioning can help to determine low-risk emission reduction options, specifically options that alter manure characteristics (e.g., reduced protein diets, anaerobic digestion, or slurry acidification). These insights supported by comprehensive emission measurement studies can help improve the effectiveness of emission abatement and harmonize strategies aimed at reducing air pollution and climate change simultaneously.

Supplementation of protease, alone and in combination with fructooligosaccharide to low protein diet for finishing pigs

Effects of adding protease with or without fructooligosaccharide (FOS) to low protein diet on growth performance, nutrient digestibility and fecal noxious gas emission were evaluated in 160 finishing pigs (57.70 ± 1.16 kg) in a 9-week study. Pigs were randomly divided into four dietary treatments, PC: positive control diet (15.97% crude protein (CP)); NC: negative control diet (12.94% CP); PRO: NC supplemented with 0.05% protease; PROFOS: NC supplemented with 0.05% protease and 0.1% FOS. During weeks 4-9 and weeks 0-9, gain : feed ratio was impaired (P < 0.05) in pigs fed NC diet compared with those fed PC, PRO and PROFOS diets. Pigs fed PC, PRO and PROFOS diets had higher (P < 0.05) apparent total tract digestibility (ATTD) of CP than pigs fed NC diet. Pigs fed PROFOS diet had reduced (P < 0.05) ammonia emissions compared to pigs fed NC and PRO diets. These data indicate that reducing dietary CP concentrations impaired growth performance, decreased ATTD of CP and reduced ammonia emissions. Supplementation of protease in low CP diet improved growth performance and increased ATTD of CP. Dietary supplementation with protease and FOS in low CP diet improved growth performance, increased ATTD of CP and decreased fecal ammonia emission.

A review of heavy weight market pigs: status of knowledge and future needs assessment

Marketing weight is an important economic variable that impacts the productivity and profitability of finishing pig production. Marketing weight has been increasing worldwide over the past decades driven by the dilution of fixed production cost over more weight per pig and the improvement of genetic selection of lean-type pigs. This review was aimed to summarize current knowledge and assess the future research needs on producing finishing pigs with marketing weight greater than 130 kg. Based on a thorough literature review, increasing marketing weight affected overall pig growth; in particular, cumulative average daily gain (ADG) decreased by 4.0 g, average daily feed intake (ADFI) increased by 78.1 g, and gain-to-feed ratio (G:F) decreased by 0.011 for every 10 kg increase of marketing weight. Increasing marketing weight by 10 kg increased carcass yield by 0.41% units, backfat by 1.8 mm, longissimus muscle (LM) area by 1.9 cm², carcass length by 2.2 cm, and belly yield by 0.32% units, but decreased percentage of fat-free-lean by 0.78 units and decreased loin, shoulder, and ham yields by 0.13, 0.16, and 0.17% units, respectively. Studies that investigated the effects of marketing weight on pork quality observed decreased pH by 0.02 and 0.01 at 45 min and 24 h postmortem, respectively, and increased a* value by 0.28 per 10 kg marketing weight increase. Heavier market pigs had increased concentrations of saturated fatty acids and intramuscular fat. However, studies reported conflicting results for L* and b* values, drip loss, Warner-Bratzler shear force, and sensory properties of pigs in response to increasing marketing weight. A limited amount of research has been conducted to estimate nutrient requirements for pigs greater than 140 kg. Increased weight and size of heavy pigs can create challenges to farm and packer facilities and equipment. Discussions and recommendations are provided concerning the adjustments for floor and feeder space, barn design, ventilation, disease control, transportation, and carcass processing needed for increasing marketing weight. In conclusion, increasing marketing weight creates both opportunities and challenges to current finishing pig production, and future research is needed to provide nutritional and management guidelines and improve feed efficiency and meat quality of heavy weight market pigs.

Environmental impact of heavy pig production in a sample of Italian farms. A cradle to farm-gate analysis

Four breeding piggeries and eight growing-fattening piggeries were analyzed to estimate potential environmental impacts of heavy pig production (>160kg of live height at slaughtering). Life Cycle Assessment methodology was adopted in the study, considering a system from breeding phase to growing fattening phase. Environmental impacts of breeding phase and growing-fattening phase were accounted separately and then combined to obtain the impacts of heavy pig production. The functional unit was 1kg of live weight gain. Impact categories investigated were global warming (GW), acidification (AC), eutrophication (EU), abiotic depletion (AD), and photochemical ozone formation (PO). The total environmental impact of 1kg of live weight gain was 3.3kg CO2eq, 4.9E-2kg SO2eq, 3.1E-2kg PO4(3-)eq, 3.7E-3kg Sbeq, 1.7E-3kg C2H4eq for GW, AC, EU, AD, and PO respectively. Feed production was the main hotspot in all impact categories. Greenhouse gases responsible for GW were mainly CH4, N2O, and CO2. Ammonia was the most important source of AC, sharing about 90%. Nitrate and NH3 were the main emissions responsible for EU, whereas P and NOx showed minor contributions. Crude oil and natural gas consumption was the main source of AD. A large spectrum of pollutants had a significant impact on PO: they comprised CH4 from manure fermentation, CO2 caused by fossil fuel combustion in agricultural operations and industrial processes, ethane and propene emitted during oil extraction and refining, and hexane used in soybean oil extraction. The farm characteristics that best explained the results were fundamentally connected with performance indicators Farms showed a wide variability of results, meaning that there was wide margin for improving the environmental performance of either breeding or growing-fattening farms. The effectiveness of some mitigation measures was evaluated and the results that could be obtained by their introduction have been presented.

Effect of progressive reduction in crude protein and lysine of heavy pigs diets on some technological properties of green hams destined for PDO dry-cured ham production

In order to investigate the effects of dietary crude protein (CP) and lysine (Lys) content on some technological properties of green hams destined for Protected Designation of Origin (PDO) dry-cured ham, green hams visual appraisal scores, thickness, iodine number and fatty acid composition of subcutaneous fat, and ham weight losses during seasoning (SL) were assessed. The green hams were obtained from 233 pigs fed four diets containing 140 to 110g/kg CP and 6.5 to 5.3g/kg total Lys from 90 to 165kg body weight. A reduction in dietary CP and Lys of up to 20% compared with conventional feeds led to a 15% increase in the thickness of the subcutaneous fat, a 5% decrease in linoleic and polyunsaturated fatty acids in subcutaneous fat and a 7% decrease in SL. A 20% reduction of CP and Lys in diets for finishing pigs has positive effects on the technological properties of green hams destined for PDO dry-cured ham production.

Evaluation of collection method and diet effects on apparent digestibility and energy values of swine diets

Two experiments were conducted to investigate the effects of collection method and diet type on digestibility coefficients. In Exp. 1, 24 barrows were fed either a corn-soybean meal (CSBM) diet or CSBM with 20% dried distillers' grains with solubles (CSBM-DDGS). In Exp. 2, the effects of basal diet and collection method on determination of dried distillers' grains with solubles (DDGS) digestibility were studied using 24 barrows. The 4 diets used in Exp. 2 were: a CSBM (basal 1) , a barley-canola meal (BCM; basal 2), 80% basal 1 with 20% DDGS (CSBM-DDGS), and 80% basal 2 with 20% DDGS (BCM-DDGS). In both experiments, feces were collected using a time-based collection method (DY) or a "marker-to-marker" collection method (MM). Diets contained 0.5% of titanium dioxide (TiO) for estimating digestibility using the index marker approach (IM). The apparent total tract digestibility (ATTD) of DM and GE were lower ( < 0.05) in the CSBM-DDGS diet than in the CSBM diet in Exp. 1 but were not different in Exp. 2. All the estimates of BCM-based diets were consistently lower ( < 0.05) than those of CSBM-based diets. In Exp. 1, digestibility coefficients determined by the DY and MM were not different from each other, whereas those estimates were lower ( < 0.05) using the IM than those using the total collection approach (TC; DY and MM). In Exp. 2, interactions ( < 0.05) were observed between diet type and method for dietary digestibility coefficients. Digestibility and energy values estimated by the DY and MM were not different in pigs fed CSBM-based diets and the BCM-DDGS diet, whereas those estimates were greater ( < 0.05) using the DY than those using the MM in pigs fed the BCM. There were no interactions between basal diet and method for estimating DDGS digestibility. The ATTD of DM and GE of DDGS using the MM were greater ( < 0.05) than those using the IM, and ATTD of N tended to be greater ( < 0.10) using the MM than that using the IM. All estimates using the DY were not different from those using the MM or the IM, except that DE of DDGS was greater ( < 0.05) using the DY than when using the IM. Digestibility estimates of DDGS were not affected by basal diets. The mean DE and ME (as-fed basis) of DDGS were 3,994 and 3,688 kcal/kg, respectively, when estimated using the basal 1 diet and were 3,919 and 3,547 kcal/kg, respectively, when estimated using the basal 2 diet. In conclusion, both collection methods can be used to estimate energy and nutrient digestibility of diets and DDGS when using CSBM-based diets.

Influences of dietary protein sources and crude protein levels on intracellular free amino acid profile in the longissimus dorsi muscle of finishing gilts

BACKGROUND

The current study was carried out to determine effects of dietary protein source and crude protein (CP) level on carcass characteristics, meat quality, and muscle amino acid (AA) profile in finishing gilts. The experiment was designed as a 2 × 2 factorial arrangement with two sources of dietary proteins (cottonseed meal, CSM vs. soybean meal, SBM) and two levels of CP (12 % vs. 14 %, as-fed basis). Seventy-two crossbred gilts (89.5 ± 0.9 kg) were allotted to one of four dietary treatments in a randomized complete block design for a period of 28 d. All diets were formulated to be isoenergetic and similar concentrations of standardized ileal digestible essential AA covering the nutrient requirements of pigs.

RESULTS

Growth, carcass characteristics and meat quality were not affected by dietary protein source nor crude protein level (P > 0.10) except that average daily feed intake was increased by CSM diets (P = 0.03). Gilts offered reduced protein diets had lower muscle pH45min (P < 0.05). Neither dietary protein source nor crude protein level influenced N deposition. However, reduced protein diets decreased N intake, N excretion, and serum urea nitrogen content, whilst improved N efficiency (P < 0.01). CSM diets increased N intake (P = 0.04), but did not depress N efficiency. The concentrations of phenylalanine, tryptophan, cysteine and tyrosine (P < 0.05) of the longissimus muscle were decreased when gilts offered CSM diets, while muscle intracellular free valine concentration was increased (P = 0.03). The gilts offered reduced protein diets had greater intracellular concentrations of free methionine, lysine, and total AA in muscle (P < 0.05).

CONCLUSION

These results suggest that CSM could replace SBM as a primary protein source in finishing pig diets in terms of performance, N efficiency, carcass characteristics, and meat quality, but decrease the concentrations of muscle specific AA. Furthermore, the reduced protein diet played an important role in increasing muscle intracellular concentrations of specific free amino acids (FAA), and in reducing the relative ratios of specific FAA to lysine in longissimus dorsi muscle of pig, whose biological meaning needs further studies.

Low-protein diets affect ileal amino acid digestibility and gene expression of digestive enzymes in growing and finishing pigs

The objective of this study was to evaluate effects of dietary crude protein (CP) intake on ileal amino acid digestibilities and expression of genes for digestive enzymes in growing and finishing pigs. In Experiment 1, 18 growing pigs (average initial BW = 36.5 kg) were assigned randomly into one of three treatments (n = 6/treatment group) representing normal (18 % CP), low (15 % CP), and very low (12 % CP) protein intake. In Experiment 2, 18 finishing pigs (average initial BW = 62.3 kg) were allotted randomly into one of three treatments (n = 6/treatment group), representing normal (16 % CP), low (13 % CP) and very low (10 % CP) protein intake. In both experiments, diets with low and very low CP were supplemented with crystalline amino acids to achieve equal content of standardized ileal digestible Lys, Met, Thr, and Trp, and were provided to pigs ad libitum. Daily feed intake, BW, and feed/gain ratios were determined. At the end of each experiment, all pigs were slaughtered to collect pancreas, small-intestine samples, and terminal ileal chymes. Samples were used for determining expression of genes for digestive enzymes and ileal amino acid digestibilities. Growing pigs fed the 12 % CP and 15 % CP diets had lower final body weight (P < 0.01) and ADG (P < 0.0001) when compared with pigs fed the 18 % dietary CP diet. Growing pigs fed with the 12 % CP diet showed higher digestibilities for CP (P < 0.05), DM (P < 0.05), Lys (P < 0.0001), Met (P < 0.01), Cys (P < 0.01), Thr (P < 0.01), Trp (P < 0.05), Val (P < 0.05), Phe (P < 0.05), Ala (P < 0.05), Cys (P < 0.01), and Gly (P < 0.05) than those fed the 18 % CP diet. Finishing pigs fed the 16 % CP diet had a higher (P < 0.01) final body weight than those fed the 10 % CP diet. mRNA levels for digestive enzymes (trypsinogen, chymotrypsin B, and dipeptidases-II and III) differed among the three groups of pigs (P < 0.05), and no difference was noted in the genes expression between control group and lower CP group. These results indicated that a reduction of dietary CP by a six-percentage value limited the growth performance of growing-finishing pigs and that a low-protein diet supplemented with deficient amino acids could reduce the excretion of nitrogen into the environment without affecting weight gain.

Response of laying hens to feeding low-protein amino acid-supplemented diets under high ambient temperature: performance, egg quality, leukocyte profile, blood lipids, and excreta pH

An experiment was conducted to determine whether, by using a low-protein amino acid-supplemented diet, the health status, stress response, and excreta quality could be improved without affecting the productive performance of heat-stressed laying hens. The requirements for egg production, egg mass, and feed conversion ratio were also estimated using second-order equations and broken-line regression. A total of 150 Lohmann Selected Leghorn (LSL-Lite) hens were divided randomly into five groups of 30 with five replicates of six hens. The hens were raised for an 8-week period (52 to 60 weeks) in wire cages situated in high ambient temperature in an open-sided housing system. The five experimental diets (ME; 2,720 kcal/kg) varied according to five crude protein (CP) levels: normal-CP diet (control, 16.5 % CP) and low-CP diets containing 15.0, 13.5, 12.0, or 10.5 % CP. All experimental diets were supplemented with crystalline amino acids at the levels sufficient to meet their requirements. The results showed that under high temperature conditions, all productive performance and egg quality parameters in the birds fed with 15.0, 13.5, and 12.0 % CP diets were similar to those of birds fed with control diet (16.5 % CP), whereas feeding 10.5 % CP diet significantly decreased egg production and egg mass. Estimations of requirements were of 13.93 and 12.77 % CP for egg production, 14.62 and 13.22 % CP for egg mass, and 12.93 and 12.26 % CP for feed conversion ratio using quadratic and broken-line models, respectively. Egg yolk color index, blood triglyceride level, and excreta acidity were also significantly higher in birds fed with 12.0 and 10.5 % CP diets compared with those of control birds. The heterophil to lymphocyte ratio, as a stress indicator, was significantly decreased by 15.0, 13.5, and 12 % CP diets. On the basis of our findings, reducing dietary CP from 16.5 to 12.0 % and supplementing the diets with the essential amino acids showed merit for improving the stress response and excreta quality while maintaining acceptable production performance from laying hens under high ambient temperature conditions.

Mitigation of ammonia, nitrous oxide and methane emissions from manure management chains: a meta-analysis and integrated assessment

Livestock manure contributes considerably to global emissions of ammonia (NH3 ) and greenhouse gases (GHG), especially methane (CH4 ) and nitrous oxide (N2 O). Various measures have been developed to mitigate these emissions, but most of these focus on one specific gas and/or emission source. Here, we present a meta-analysis and integrated assessment of the effects of mitigation measures on NH3 , CH4 and (direct and indirect) N2 O emissions from the whole manure management chain. We analysed the effects of mitigation technologies on NH3 , CH4 and N2 O emissions from individual sources statistically using results of 126 published studies. Whole-chain effects on NH3 and GHG emissions were assessed through scenario analysis. Significant NH3 reduction efficiencies were observed for (i) housing via lowering the dietary crude protein (CP) content (24-65%, compared to the reference situation), for (ii) external slurry storages via acidification (83%) and covers of straw (78%) or artificial films (98%), for (iii) solid manure storages via compaction and covering (61%, compared to composting), and for (iv) manure application through band spreading (55%, compared to surface application), incorporation (70%) and injection (80%). Acidification decreased CH4 emissions from stored slurry by 87%. Significant increases in N2 O emissions were found for straw-covered slurry storages (by two orders of magnitude) and manure injection (by 26-199%). These side-effects of straw covers and slurry injection on N2 O emission were relatively small when considering the total GHG emissions from the manure chain. Lowering the CP content of feed and acidifying slurry are strategies that consistently reduce NH3 and GHG emissions in the whole chain. Other strategies may reduce emissions of a specific gas or emissions source, by which there is a risk of unwanted trade-offs in the manure management chain. Proper farm-scale combinations of mitigation measures are important to minimize impacts of livestock production on global emissions of NH3 and GHG.

Effect of the generation and physical-chemical characterization of swine and dairy cattle slurries on treatment technologies

Differences in biodegradability can affect the treatment of slurry before its use in spraying. The objective of this study was to evaluate the effect of the generation and physical-chemical characterization of swine and dairy cattle slurries on different biological treatment technologies. This research involved monthly sampling (number/composition) for 1 year of 24 swine farms (16%), cattle farms (38%), and mixed swine and cattle farms (46%). The results obtained showed differences in feeding (3 l water kg(-1) food for cattle and 5 l water kg(-1) food for swine) and assimilation (0.6 kg food kg (-1) milk produced and 3 kg kg(-1) weight gain), which may influence the generation of slurry (57 l animal(-1)d(-1) in cattle and 31 l animal(-1) d(-1) in swine) and its composition. In addition, the composition of swine slurry [23 g chemical oxygen demand (COD) l(-1), 3 g total nitrogen (TN) l(-1)] is significantly different (P < 0.01) to cattle slurry (4 g COD l(-1), 0.3 g TN l(-1)). Finally, the composition and the S index applied to swine slurry [COD N(-1) = 8, biological oxygen demand (BOD)5 COD(-1) = 0.3, S index > 0] and cattle slurry (COD N(-1) = 16, BOD5 COD(-1) = 0.6, S index < 0) show a difference on the biodegradability of both slurries. Suitability of anaerobic and aerobic treatment was assessed based on the findings.

Microencapsulated lysine and low-protein diets: effects on performance, carcass characteristics and nitrogen excretion in heavy growing-finishing pigs

Two studies were conducted to assess the effects of dietary protein and Lys reduction on growth performance, carcass quality, N excretion, and plasma N profile in growing-finishing pigs from 35 to 180 kg. The growing trial was conducted with 72 gilts and 72 barrows with 6 pens per treatment and 6 gilts or 6 barrows per pen. Four diets with the same DE and NE were compared: 1) control diet, 2) diet with protein content reduced by 3% units compared with the control diet and supplemented with Lys HCl to match the requirements according to the 2012 NRC (FLys), 3) diet similar to FLys for protein level but supplemented with only 50% of the Lys HCl provided with FLys (-50% FLys), and 4) diet similar to FLys and -50% Flys for protein level with microencapsulated Lys added to supply 20% of the Lys provided by FLys (-80% MLys). Pigs fed the FLys diet performed in a similar manner and showed similar carcass characteristics to the control pigs. Pigs fed the -50% FLys diet had the lightest BW (P < 0.01) as well as the lightest carcass (P = 0.02) and trimmed thigh (P = 0.04) weights. Pigs fed the -80% MLys diet showed growth performance and carcass characteristics similar to the control pigs. The N balance study was conducted with 8 barrows arranged in a double replicated 4 × 4 Latin square design. The control pigs had greater (P < 0.01) N intake and urinary and total N excretion compared with pigs fed the low-protein diets. The reduction of the dietary protein concentration by 3% units decreased total N excretion by an average of 24.5% and the greatest reduction of total N excretion was obtained by the -80% MLys diet (26.12%) compared with the control diet throughout the trial. No effect of dietary treatment was observed on the plasma concentrations of ammonia, urea, and total AA in the 80-kg pigs. Decreased plasma ammonia (P < 0.01) and urea (P = 0.03) concentrations were detected in the 120-kg pigs fed the low-protein diets. The 160-kg pigs fed the -80% MLys pigs had less total AA, indispensable AA in particular (P < 0.01), than pigs fed the other diets and decreased ammonia (P < 0.01) and urea (P = 0.05) concentrations than the control pigs. The results showed that the use of microencapsulated Lys, compared with both Lys HCl and dietary protein-bound Lys, can save CP and synthetic AA in diet formulation and can reduce N excretion in manure without adversely affecting the growth performance and carcass quality of heavy growing-finishing pigs.