Defining Amino Acid Requirements of Pregnant Sows: Challenges and Opportunities

The efficient use of protein in animal production is dependent on the protein supply and its constituent amino acids (AA) in relation to the animal\u27s needs. Excess AA are deaminated, and the resulting nitrogen (N) is excreted, whereas suboptimal AA intake reduces animal performance. Both increased nutrient excretion and decreased animal performance reduce the overall efficiency of the production unit. In sows, AA requirements should be adequate for optimizing reproductive performance, as measured, for example, by the number of pigs produced per sow per year while limiting N excretion. There is a desire to feed pregnant sows AA levels that meet both physiological needs and environmental considerations. Current methods for estimating AA requirements, however, are geared toward reducing N excretion, rather than optimizing reproductive performance. Minimizing N excretion increases N utilization efficiency but decreases overall meat production efficiency if these dietary levels do not maximize pregnant sow reproductive performance. Thus, the overall objective of this dissertation is to increase our understanding on the dynamics of N excretion and retention across gestation and to determine dietary AA levels that optimize reproductive performance. To accomplish these objectives a series of in silico and in vivo studies were performed and are outlined in four research chapters (Chapter 2, 3, 4, and 5). In Chapter 2, a mechanistic model was developed to quantify and characterize the N and AA deposition in the different tissue pools that make up the pregnant sow as well as their interaction in terms of nutrient competition: placenta, allantoic fluid, amniotic fluid, fetus, uterus, mammary gland, and maternal body were considered. Growth curves for each tissue were developed, as well as curves describing retention of the 10 essential AA and N for each tissue. The growth and nutrient retention curves were developed as a function of the model\u27s inputs: parity, body weight (BW) at breeding, litter size, average piglet birth weight, and number of available teats. All functions were combined in an algorithm that dynamically distributed the dietary N and AA to the different tissues based on the inputs of the model. The model characterized a trend in maternal N retention that could not be previously explained, although identified as time-dependent protein deposition (Pd), by the NRC (2012) gestating sow model. The trend in N retention described by the time-dependent protein pool appears to be due to a drop in daily N retention, particularly during early gestation, rather than increased N retention, as previously thought, implying that current energy and/or AA requirements for early pregnancy should be reviewed. In Chapter 3, a dose-response curve defined as the linear-logistic model was developed based on experimental data from pregnant gilts at d 50 of gestation to describe the response of N retention to graded levels of the AA lysine (Lys). The linear-logistic model describes two inflection points defined as: 1) N retention max (NRmax) and 2) N retention minimum (NRmin). Based on the hypothesis that Lys intakes corresponding to NRmax maximized maternal body growth and Lys intakes corresponding to NRmin maximized the reproductive performance of pregnant sows, a meta-analysis was performed. The standardized ileal digestible (SID) Lys requirements for sows throughout gestation were calculated using the linear-logistic model and observations from Chapter 2. The meta-analysis confirmed that SID Lys levels corresponding to NRmax and NRmin maximized maternal growth and reproductive performance, respectively. Because current AA requirements are more likely to represent NRmax, current AA requirements appear to optimize maternal lean tissue deposition rather than conceptus development. Optimal reproductive performance appears to occur at AA levels above current recommendations. In Chapter 4, a study was performed to test model outputs from Chapters 2 and 3 and investigate the effects of SID methionine (Met) intakes greater than current requirements on the metabolic status of gilts at breeding age. The metabolic status of the animals was evaluated using plasma AA concentration, with a particular emphasis on plasma taurine (Tau) which is a non-proteogenic AA that is biosynthesized from Met and regulates a variety of functions in the body. In addition, the dynamics of N retention at potential SID Met intakes that maximize Tau biosynthesis were investigated. The results of this study showed that SID Met intakes corresponding to 230% of current requirements maximized Tau biosynthesis and, thus, potentially Tau-related metabolic functions, and resulted in a decrease in whole-body N retention. Optimal metabolic status appears to occur at AA levels above current recommendations. In Chapter 5, a pilot study was performed to study the effects of SID Met intake levels corresponding to 230% of the requirement for gilts during the first 90 days of gestation on sow BW gain. A total of 39 sows were provided either a control or a high Met diet. Sows in the control group gained in average 1.67 kg more than those in the high Met group (P=0.070). The reduced BW gain in the high Met group may be explained by a decrease in the priority for maternal body deposition and an increase in reproductive function and metabolic status, as predicted in Chapter 3 and 4. However, due to a disease outbreak in the research herd, the effects of dietary SID Met on litter size could not be determined and the previous claim could not be fully supported. In summary, the developed mechanistic model enhanced understanding of the dynamics of N retention across gestation. Observations made in all four research chapters suggest that current AA requirements are underestimated when metabolic status and reproductive function are considered. In Chapter 3, 4 and 5 it is suggested that at optimal AA intake for metabolic and reproductive status there is a decrease in the efficiency of N utilization (i.e. increased N excretion). As a result, it is advised that AA requirements based on maximal N efficiency may be limiting sow performance. The linear-logistic model is proposed as an analytic tool for the estimation of dietary AA requirements that maximize reproductive performance and metabolic status. The SID Lys requirements estimated using the linear-logistic model and the SID Met requirements empirically estimated using plasma Tau measurements have the potential to improve pregnant sow reproductive performance

Protein growth in pigs

The following aspects of protein growth in pigs were examined:I. Shape of daily protein and lean deposition rate against age and live weight. 45 Large White pigs were fed to appetite; littermate trios were serially slaughtered between 55 and 330 days of age. Daily feed intakes increased linearly until 140 days and 85 kg LW. Daily protein and lean gains, 55-195 days and 20-150 kg, were 0.128, 0.255 (boars), 0.108, 0.221 (g ilts ), 0.117, 0.234 (castrates). Dissected lean was 2.21 total body protein. Estimated MEm value, 0.545 MJME per kg W⁰⁷⁵ d⁻¹; kp was 0.27 and kl, 0.73.II. Body composition after weaning. Weight stasis concealed substantial lipid loss from carcass fatty tissue and continued growth of carcass muscle plus bone. Recovery from post-weaning growth check was more rapid when diets of high nutrient density were offered. Thirty-five female pigs were given 4 intake treatments and serially slaughtered between 25 and 70 days. During refeeding previously-restricted pigs gained 75.4 g protein d-1; appetite-fed controls gained 67.4 g d-1. Refed pigs did not consume more food, or deposit protein more rapidly, than controls of the same age or body weight. Twenty-eight pairs of entire male pigs were grown from 5.6 to 25 kg on two diets of differing ingredient composition and nutrient density. There were no differences in carcass composition at 25 kg or daily feed intake (0.81 vs 0.76 k g ). Pigs fed the diet of higher ingredient quality and nutrient density reached 25 kg fourteen days sooner and ate 8.9 kg less in total. Postweaning growth was constrained by the poorer quality diet.III. Compensatory nitrogen retention. Seventy-one Large White barrows were fed various sequences of dietary nitrogen intakes over 30 days. Following nitrogen deprivation, compensating animals retained 2.7 (Trial 1) and 4.2 (Trial 2) g N d-1 more than controls. Evidence suggests extra nitrogen to be used to replenish labile nitrogen stores depleted during nitrogen deprivation

Possibilities and limitations of protein supply in organic poultry and pig production

It is one of the general recommendations in animal nutrition that the diet should be formulated according to the specific requirements of animals at the various stages of their development. To which degree the farmer can adapt the nutrient supply to the specific requirements of the animals depends primarily on the production goal and on the availability of nutrient resources. This report gives a general introduction to the present situation for dietary protein supply to poultry and pig production in relation to the principles for organic agriculture and husbandry production. Furthermore it includes partly literature based on research from conventional animal production, as the requirements on the level of the animals are not different in both systems. Moreover, there only few research projects of organic production systems available. This report is primarily focussing on the question whether a nutrient supply of 100% organic feed can and should be realised. In this context, it is not possible to cover all aspects in detail as the report cannot replace a textbook. The main emphasis is laid on a coherent argumentation based on the leading ideas of organic agriculture. Concerning further relevant aspects it is referred to the report ”Supply and demand for concentrated organic feed in the EU in 2002 and 2003” by Susanne Padel as part of the same EU-project: ‘Research to support the EU-regulation on Organic Agriculture’ (www.organic-revision.org) and to the project “Availability of organically reared livestock” (S. Gomez, JRC, Institute for Prospective Technological Studies, this study is expected to be completed in November 2005). In conventional animal production, a nutrient supply that is closely related to the requirements is an important tool in the performance-oriented production (FLACHOWSKY, 1998). The objective of animal nutrition is to adapt the nutrient supply as accurately as possible to the requirements resulting from maintenance and performance need. Soybean meal, due to the high protein content and high protein quality, has developed into the most important protein source in the nutrition of monogastric animals. Additionally, synthetic amino acids (DL-methionine) and industrial amino acids (produced from microbial fermentation, L-amino acids) are used to balance the supply of essential amino acids. While the use of soybean meal and synthetic amino acids is normal practice in conventional animal production, the Council-Regulation No. 2092/91, amended by Council Regulation No. 1804/99 on organic livestock production bans the use of chemically extracted soybean meal and synthetic amino acids on organic farms as livestock must be fed primarily on organically produced feedstuffs (Annex 1, paragraph 4.2). By way of a derogation from paragraph 4.2, for a transitional period expiring on 24 August 2005, the use of a limited proportion of non-organic feedstuffs is authorised where farmers can show to the satisfaction of the inspection body that they are unable to obtain feed exclusively from organic production (paragraph 4.8). The derogation, although with a declining percentage of non-organic feedstuffs over the next years, has been prolonged in July 2005. The preferable use of home-grown feedstuffs and limitations in the choice of boughtin feedstuffs can be the cause of considerable variation in the composition of the diets, and considerably restrict the possibilities for the adaptation of the feed ration to the specific requirements. Due to the limited availability of essential amino acids in particular, there is concern that nutritional imbalances encountered in practice might lead to deteriorating animal health and welfare. On the other hand, there is also the concern that allowing conventional feedstuffs to be fed in organic livestock production will result in intensification of production. The intensification might cause the same problems in organic production as conventional production already shows (animal health problems, risk of residues and GM contamination etc.). Thus, the use of non-organic feedstuffs may have a damaging effect on consumer confidence in organic products of animal origin. In the following the nutritional-physiological effects of a variation in protein supply with respect to growth performance and protein accretion in broilers, turkeys, laying hens, and pigs are examined by means of a literature review. Additionally, the potential effects of the protein content in the diet on product quality, animal health and environmental damage are addressed. It is the aim of the report to provide an overview of the many different aspects of the protein supply in organic poultry and pig production. Many different aspects are taken into account to elaborate possibilities to handle the use of organic and non-organic feedstuffs with respect to the objectives and framework conditions of organic livestock production. However, due to the complex interactions not all aspects can be covered. There is room and need for explanation and for further research

The influence of rumen volatile fatty acids on protein metabolism in growing lambs

The effect of acetic or propionic acid rumen fermentation patterns on whole-body protein turnover, tissue protein synthetic rates and body composition was investigated in growing lambs. Protein turnover was assessed using a continuous intravenous infusion of [2,3-³H]tyrosine and tissue protein fractional synthetic rates (FSR) from the specific activities of plasma free, intracellular free and tissue bound tyrosine. Only the FSR of muscle tissue approached significance. The high FSR in the propionic group was attributed to the high plasma insulin concentration. Values for whole-body protein synthesis, corrected for tyrosine oxidation, were similar to those obtained by summating protein synthesis in individual tissues, confirming that tyrosine oxidation should be measured accurately if reliable whole-body protein synthesis values are required. Tyrosine oxidation and flux were high in the acetic acid group, suggesting that amino acids are used for gluconeogenesis. The high protein turnover rate probably ensures an adequate supply of gluconeogenic amino acids and that the penalty of mobilizing body proteins for gluconeogenic amino acids is minimal. In the propionic acid group, high plasma glucose and insulin concentrations were associated with a low protein turnover rate, high ratio of deposited: synthesized protein and a high body fat content. It is concluded that changing the proportion of ruminal volatile fatty acids influences protein turnover, protein synthesis and the efficiency of protein retention. Such factors probably contribute, indirectly, to the observed differences in body composition

Feeding monogastrics 100% organic and regionally produced feed

The transition to 100% organic feed ingredients for organic livestock is expected to take effect from January 1st 2020 in Europe. In order to contribute to the goal of 100% use of organic and regional feed for monogastrics, this knowledge synthesis “Feeding monogastrics 100% organic and regionally produced feed“ aims to describe: • the protein need for organic monogastric animals (pigs, layers and broilers), including different breeds and rearing conditions • different protein feed resources, mostly new or not commonly used protein sources, their nutrient content, production prerequisites, and their potential feeding value • small-scale, on-farm equipment for feed processing • different feeding strategies. The knowledge synthesis should enable participants in Innovation groups (IG) and Thematic groups (TG) to choose feed materials, feeding strategies, breeds and perhaps even small-scale on-farm equipment for testing when aiming at 100% organic and regionally produced feed for monogastrics. In the knowledge synthesis it is concluded: When feeding pigs and poultry 100% organic and regionally produced feed, getting enough protein and specific amino acids is a challenge. There are two ways to go and they can be combined. One is to utilize by-products, for example waste from various productions, and explore new protein sources e.g. marine products or to refine already known products such as grass. The other way is to feed the animals less intensively and for this feeding strategy slow-growing breeds fit better. Some slow-growing breeds are already known, some are rediscovered old breeds. The challenge with the slow-growing and less-yielding breeds is that the production is getting smaller and either the farmer will earn less or the prices of eggs and meat will increase. However, the possibilities for combinations of regionally grown feed, low-yielding breeds with different feeding strategies are many and they need to be explored. Finally, the knowledge synthesis identify needs for new knowledge on: • nutritional requirements of alternative breeds. Precise nutrient recommendations for organically produced pigs and poultry do not exist. • nutritional value of new protein sources for monogastric animals • various combinations of breeds, grazing and supplemental feed. Small-scale on-farm equipment to refine locally produced raw materials needs to be developed

Detection and Treatment of Mineral Nutrition Problems in Grazing Sheep

Livestock Production/Industries,

The effect of crude protein and metabolizable energy levels on the efficiency of nitrogen retention and energy utilization by the weanling pig

A metabolism trial was conducted with young pigs to evaluate the effect of crude protein and metabolizable energy (ME) levels on the efficiency of protein and energy utilization. In each of three replicates, six littermate barrows, with weights averaging 14.6, 18.4 and 27.1 kg, respectively, were individually fed one of six diets. The diets, representing a factorial arrangement of two levels of crude protein (150 and 180 g/kg) and three levels of energy (3000, 3300 and 3600 kcal ME/kg), were formulated to maintain a constant ratio of fat calories to carbohydrate calories across all treatment effects. Each replicate, randomly assigned to one of six identical metabolism cages, was subjected to a 5-day preliminary period and a succeeding 5-day period of collection of urine and feces. The intake of feed and gross energy (GE) was equal across all energy treatments. Pigs fed higher levels of ME retained more GE than did pigs fed lower levels of ME. Nitrogen (N) intake, excretion and balance were equal among all energy subcells, as was the percent of ingested N that was retained. Nitrogen retention efficiency (NRE, g N retained per Meal GE metabolized) decreased inversely with ME content of the diet. The energetic efficiency of ME for fat deposition was greatest when the magnitude of the calorie:protein ratio was highest. Feed and GE intake were not affected by the protein content of the diet. The fractional amount of GE digested and metabolized did not differ between the two protein levels. The amount of GE retained increased within each protein level as the caloric density of the diets increased. The amount of N consumed, excreted and retained was less in pigs fed the 15 percent protein diets. The fractional amount of ingested N that was retained did not differ between protein levels. Pigs fed the 18 percent protein diets had higher NRE values than did pigs fed the 15 percent protein diets. Nitrogen retention efficiency was maximized when the calorie:protein ratio was minimized, such that NRE was greatest when pigs were fed diets containing 18 percent protein and 3000 kcal ME. Pigs fed treatments differing in the amount of energy and protein per kg of diet, but still made-up to contain equivalent calorie:protein ratios, had equal measures of NRE. Amounts of feed, GE intake, GE retained (metabolized energy), N intake, N excretion and N balance increased with increasing pig liveweight. Pigs weighing 14.6 kg, on a percentage basis, retained more ingested N than did pigs weighing 18.4 or 27.1 kg. Both the fractional amount of GE which was consumed and metabolized and the values for NRE were not affected by pig weight

Amino Acid and Energy Interrelationships in Pigs Weighing from 20 to 50 Kilograms: Rate and Efficiency of Protein and Fat Deposition

Two experiments were conducted to investigate the relationships between amino acids and DE for pigs weighing 20 to 50 kg. In Exp. 1, there were three dietary lysine levels that were either adjusted (1.50, 2.35 and 3.20 g/Mcal DE) for five DE levels (3.00 to 4.00 Mcal/kg) or unadjusted (.45, .71 and .%% of the diet) for three DE levels (3.50 to 4.00 Mcal/kg). In Exp. 2, diets containing six 1ysine:DE ratios (1.90 to 3.90 g/Mcal) at two DE levels (3.25 and 3.75 Mcal/kg) were fed. Pigs were housed individuiiy, and could eat and drink ad libitum. When pigs weighed 50 kg, their empty body composition was determined by the urea dilution technique in Exp. 1 and by prediction equations based on backfat in Exp. 2. For the adjusted diets in Exp. 1, protein deposition and protein deposition:DE intake increased (P \u3c .01) slightly as DE levels increased. These criteria decreased linearly (P \u3c .001), and fat deposition increased (P = .11) as DE increased when 1ysine:DE ratios were not maintained. As lysine levels increased, protein deposition and protein deposition: DE intake increased (P \u3c .001) in both the adjusted and unadjusted diets. In Exp. 2, there was no effect of DE on either the rate or efficiency of protein deposition. Both protein deposition and protein deposition: DE intake increased (P \u3c .001) and fat deposition decreased as 1ysine:DE ratios increased up to 3.00 g lysine/Mcal DE. Protein deposition: lysine intake decreased (P \u3c .01) progressively as the 1ysine:DE ratio increased. Regression analyses indicated that protein deposition increased up to 3.00 g 1ysineMcal DE. The results demonstrate the need to adjust lysine according to energy levels and indicate that the optimum ratio for protein deposition was approximately 3.00 g lysine/Mcal DE (or 49 g of balanced protein/Mcal DE)