Essential Amino Acid Composition Research Articles

Underutilised legumes: potential sources for low-cost protein

Seeds of 104 leguminous species belonging to 17 genera were analysed for their protein contents. The promising ones were investigated for fibre, carbohydrate, ash, oil, fatty acids, amino acid profile and trypsin inhibitor activity (TIA). The variation of fibre contents was 4.1-8.9%, carbohydrate 18.4-49.2%, ash 1.8-7.2%, TIA 48.7-87.5 mg/g, oil 1.3-19.8% and protein 11.0-51.6%. The protein content (41-45%) in Acacia mellifera (41.6%), Albizzia lebbek (43.6%), Bauhinia triandra (42.7%), Lathyrus odoratus (42.8%), Parkinsonia aculeata (41.6%), Psophocarpus tetragonolobus (41.9%), Sesbania paludosa (41.2%) and S. sesban (43.8%) was in close proximity to soybean (42.8%), whereas Bauhinia retusa (51.6%), B. variegata (46.5%), Delonix elata (48.7%) and Gliricidia maculata (46.3%) showed higher percentages of protein than soybean. The essential amino acid composition of some of the seed proteins was reasonably well balanced (lysine up to 7.6%). The seeds of Bauhinia retusa (18.6%), B. triandra (16.5%), B. variegata (17.3%), Gliricidia maculata (16.2%), Parkia biglandulosa (18.9%) and Psophocarpus tetragonolobus (19.8%) had a good amount of oil, comparable to soybean (18-22%). The fatty acid composition of some genera/species was quite promising with high amount of unsaturated fatty acids.

Características químicas dos mingaus desidratados de arroz e soja

O presente trabalho teve por objetivo caracterizar quimicamente os mingaus desidratados de arroz e soja nas respectivas proporcoes 100:0, 90:10, 80:20, 70:30, 60:40 e 50:50% e verificar a possibilidade do uso de alguns destes mingaus como ingredientes na formulacao de alimentos infantis com base nos resultados discutidos. O processo utilizado para sua obtencao foi decorticagem dos graos de soja, branqueamento, desintegracao e homogeneizacao do arroz e soja, assim como secagem por atomizacao. A caracterizacao quimica foi realizada atraves das seguintes determinacoes: composicao centesimal, composicao de minerais e de aminoacidos, e atividade do inibidor de tripsina. Com o aumento das proporcoes de soja (de 0 a 50%), os mingaus desidratados tiveram aumento nos teores de proteina, extrato etereo, cinzas, fibra bruta, fosforo, calcio, potassio, magnesio, ferro, cobre, zinco, selenio, manganes e molibdenio, porem diminuicao nos teores de carboidrato, sodio e cromo. Contudo, os valores de cobalto nao foram alterados. Os teores de potassio, magnesio, ferro e cobre foram altos e os teores de cromo, selenio, manganes e molibdenio foram suficientes em 100g de mingaus desidratados de arroz e soja com 40 e 50% de soja, atendendo 100% das recomendacoes da RDA para lactentes, podendo estes formulados para alimentos infantis. Houve uma melhoria nos escores de aminoacidos essenciais com as crescentes proporcoes de soja, exceto para os aminoacidos sulfurados. A composicao em aminoacidos foi adequada e comparavel ao padrao da FAO/WHO para lactentes, exceto para lisina e metionina. Em relacao a lisina, os mingaus desidratados com 30, 40 e 50% de soja mostraram os maiores escores para pre-escolares, nao havendo deficiencia para escolares. Por outro lado, a metionina nao foi deficiente para pre-escolares e escolares. A atividade residual do inibidor de tripsina nao foi observada nos mingaus desidratados estudados.

Amino acid composition of whole body tissue of Atlantic halibut ( Hippoglossus hippoglossus), yellowtail flounder ( Pleuronectes ferruginea) and Japanese flounder ( Paralichthys olivaceus)

Amino acid and proximate composition of the whole body tissue of juvenile Atlantic halibut, yellowtail flounder and Japanese flounder were determined. Higher protein and lower lipid levels were found in whole body of Japanese flounder than the other two species. The amino acid composition was, however, not significantly different among species when expressed as g/100 g amino acids. The values were also found to be very similar to those of rainbow trout and Atlantic salmon. The A/ E ratios [(each essential amino acid content/total essential amino acid content including cystine and tyrosine)×1000] based on the essential amino acid composition of whole body tissue, suggest that the amino acid requirements of flatfish may not be greatly different among species.

The effect of protein inclusion level in diets formulated to contain an ideal amino acid composition for growing pigs

The aim of the study was to determine the optimum protein inclusion level in diets containing an ideal amino acid balance for growing pigs. The performance of commercial crossbred grower-pigs was studied in two trials in which the experimental animals were housed either in commercial-type group housing (experiment1) or in individual pens (experiment 2). Treatments consisted of diets containing 14%, 16%, 18% or 20% crude protein. Lysine, tryptophan, threonine and total sulphur-containing amino acids were included in all diets at levels equivalent to that supplied by the 18% crude protein diet. In experiment one, 144 pigs (72 boars and 72 gilts) of initial mass 30 kg were fed until slaughter at 70 kg. In experiment two, 80 pigs (40 boars and 40 gilts) of live masses ranging from 17.5 to 31.1 kg were fed until slaughter at masses between 64 and 105.5 kg. There were no differences between treatments (p > 0,05) for daily gain, feed conversion ratio, daily intake or carcass classification, but feed conversion ratio differed between sexes in experiment two (p < 0.05). It was concluded that protein inclusion levels in pig growth diets could be decreased from 18% to 14% without any detrimental effect on performance, provided that the digestible essential amino acid composition is adjusted to meet requirements. This practice is however not economically viable for South African pig producers at the prevailing price of synthetic amino acids. (South African Journal of Animal Science: 2000, 30(1): 57-61)

Homeostasis in the essential amino acid composition of the marine copepod Euterpina acutifrons

The essential amino acid composition (EAA) of females and eggs of Euterpina acutifrons and their food was analyzed on copepods fed with different microalgae and collected from the field. There were not significant differences in the EAA of females, but the EAA of eggs varied according to food source. As predicted by homeostasis theory, a higher reproductive success was observed as the EAA of females and food became more similar. This chemical homeostasis explains the selective retention of amino acids observed in copepods, tells why conversion efficiencies of ingested nitrogen may vary according to the food source, and shows the importance of food quality on reproductive success in copepods.

Examination of the nitrogen limitation hypothesis in non‐cyclic populations of cotton rats (Sigmodon hispidus)

1. Nitrogen‐containing nutrients have long been considered a frequently limiting resource to the growth of herbivore populations (nitrogen limitation hypothesis). To explore this hypothesis, we examined the relationships between availability of essential amino acids and concentrations of phenolics in the diets of hispid cotton rats (Sigmodon hispidus) in central Oklahoma and the intrinsic characteristics of their non‐cyclic populations. We posited that lower quality proteins (i.e. essential amino acid composition) and elevated phenolic levels (protein digestion inhibitors) in diets of cotton rats from low‐ compared to high‐density populations, especially during the breeding season, would be supportive of the nitrogen limitation hypothesis. Replicated low‐ and high‐density populations were censused by live‐trapping at 3‐month intervals. Samples of stomach digesta were collected from cotton rats in similar habitats adjacent to trapping grids to determine the botanical and nutrient composition of their diets. 2. During the breeding season, concentrations of essential amino acids were as much as 43% greater in diets of cotton rats from high‐density populations. Dicots, typically higher in protein than monocots, were an important component of diets and were preferred forage in all seasonal collections. Seeds and arthropods were frequently utilized by cotton rats as additional high‐quality sources of essential amino acids. Concentrations of total phenolics in the diet (greater in diets from low‐density populations) were consistent with the nitrogen limitation hypothesis. 3. Density was consistently higher in the high‐density populations throughout the study. Other demographic and body condition parameters were similar between low‐ and high‐density populations in the non‐breeding season, but reproductive activity was greater in high‐density populations during the breeding season. Total number of juveniles recruited into the trappable population over the entire study was about five times greater in high‐ compared to low‐density populations. 4. Our data did not refute the nitrogen limitation hypothesis where levels of essential amino acids and phenolic compounds in the diet during the breeding season may determine annual peak densities of cotton rats that can be supported in their habitat. However, we could not rule out the involvement of other environmental variables such as overhead cover (as well as other unmeasured variables) as contributing factors to determining annual peak densities.

Essential amino acid composition of fleshy fruits versus maintenance requirements of passerine birds

Nutritional analyses were performed on 27 fruit species that are eaten by frugivorous birds in east Mediterranean habitats in Israel. The essential amino acid (EAA) profile [compared by principal component analysis (PCA)] of these fruits indicated two distinct groups of fruits. The main group consisted of 23 species that were similar in their relatively low total EAA quantities and unbalanced EAA profiles. On average, the EAAs phenylalanine and tyrosine were most concentrated and histidine least (tryptophan was not measured). Comparing the relative amounts of EAAs in fruits with required amounts for maintenance of granivorous passerine birds revealed that these fruits are deficient in all or most EAAs. The sulfur-containing amino acids (methionine and cystine) were most limiting relative to the required amount (41–61% below requirement), while four others (arginine, lysine, isoleucine, and leucine) were severely deficient (30–37% below requirement). These results complement reports suggesting that frugivorous birds have lower total protein demands than granivores. The second group of four fruit species had relatively high total EAA contents. Each of these fruits appeared to contain especially large quantities of some EAAs, but it was uncertain whether some high concentrations could have resulted from interactions in the pulp during preparation and chemical analysis.

Free lysine ( l-lysine · HCl) is utilized for growth less efficiently than protein-bound lysine (soybean meal) in practical diets by young channel catfish ( Ictalurus punctatus)

Two 10-week feeding experiments were conducted with channel catfish fingerlings in aquaria to compare the efficiency of utilization for growth of free versus protein bound lysine in practical diets. In experiment 1, a basal, 26% protein diet, deficient only in lysine, was formulated with a combination of peanut meal and corn gluten meal as the primary protein source. The diet was then supplemented with graded levels of lysine by either adding l—lysine · HCl or substituting soybean meal for the peanut meal—corn gluten meal combination to produce two series of diets with increasing concentrations of either free lysine or protein-bound lysine. In experiment 2, the basal diet contained sesame meal as the primary protein source and was supplemented with free or protein-bound lysine as in experiment 1. Slope ratio analysis of response data showed that the efficiency of utilization of protein-bound lysine in soybean meal relative to free lysine from lysine-HCl was 196 and 163% for experiments 1 and 2, respectively, based on weight gain. A subsequent feeding experiment was conducted in which the peanut meal-corn gluten meal basal diet was supplemented with lysine alone or with lysine plus histidine, isoleucine, threonine, and tryptophan to match the essential amino acid composition of the diet in which soybean meal provided the protein. Supplementation of the basal diet with the additional amino acids did not improve fish weight gain relative to that from supplementation with lysine alone. Overfortification of the basal diet with free lysine improved weight gain of fish to equal that obtained with the diet containing soybean meal. Loss of lysine due to leaching of diets in water was 12.7 and 2.0% of the original lysine concentration for free lysine and protein-bound lysine, respectively. When leaching losses are subtracted from the lysine concentrations in the test diets, the efficiency of utilization of protein-bound lysine is still higher than that of free lysine, 175 and 146%, based on weight gain, for experiments 1 and 2, respectively. These results indicate that protein-bound lysine is more efficiently utilized than free lysine in practical type diets for young channel catfish.

Genetic and Environmental Variation for Seed Yield, Protein, Lipid and Amino Acid Composition in Cowpea (Vigna unguiculata (L) Walp)

The genetic and environmental variability for seed yield (kg ha-1), protein content (g kg-1 DM), lipid content (mg g-1 DM) and essential amino acid composition (g per 16 gN) of cowpea seeds using 15 cultivars grown in three locations (Kano (12°00′ N 8°31′ E), Mokwa (9°17′ N 5°04′ E) and Ago-Iwoye (6°58′ N 4°00′ E)) that differ markedly in climate was studied. The environmental effect accounted largely for the variability observed in yield (93%), protein (71%), lipid (100%), threonine (96%), cystine (80%) and arginine (81%) while the genotypic effect accounted largely for the variability observed in methionine (56%) and lysine (51%) contents. Correlation coefficients (pooled data) from the three locations indicated that yield was negatively correlated to protein content (r=-0·87, P<0·001) and positively correlated to lipid content (r=0·73, P<0·001). Protein content was negatively correlated to lipid content (r=-0·67, P<0·001) and positively correlated to threonine (r=0·66, P<0·01), cystine (r=0·69, P<0·001) and methionine (r=0·88, P<0·001) contents. Similarly, yield was positively correlated to threonine (r=0·22, 0·01<P<0·05), cystine (r=0·38, 0·001<P<0·01) and methionine (r=0·67, 0·001<P<0·01). Yield showed a strong negative correlation with protein content (r=-0·81) and a strong positive correlation with lipid content (r=0·97) at the environmental level. Cystine, methionine and to some extent, threonine were the limiting amino acids in the three environments. This research established the degree of variability for these characters in cowpea and indicated that concurrent selection for yield, lipid content, threonine and sulphur amino acids compositions is feasible. © 1997 SCI.

Chemical and essential amino acid composition of South African Mutton Merino lamb carcasses

Chemical and essential amino acid composition of South African Mutton Merino lamb carcasses

Dietary Influences on Endogenous Ileal Protein and Amino Acid Loss in the Pig—A Review

Abstract The basis for using determined values of endogenous ileal protein and amino acid losses in the protein evaluation of pig feeds is reviewed. The amounts of endogenous protein and amino acids in ileal digesta may be determined by numerous methods. These include N-free diets, regression analysis, enzyme hydrolysed casein (EHC) coupled with ultra-filtration, modifying lysine to homoarginine, isotope dilution techniques and calculations based on the difference between the in vitro and in vivo digestibility of protein and amino acids. Endogenous ileal protein loss seems to be influenced primarily by dietary dry matter intake and secondarily by the composition of the diet and can be divided into a basal and an extra loss. The basal loss after ingestion of experimental N-free diets is 10-15 kg−1 DM intake, but, under more physiologically normal conditions when protein-containing diets are ingested, the basal loss seems to be about 20 g kg−1 DM intake. When vegetable feedstuffs are ingested there is often an extra loss specifically induced by the presence of dietary fibre and/or antinutritional factors (ANFs), resulting in total losses that are typically in the range of 20 to 40 g kg−1 DM intake. The amino acid composition of endogenous protein is relatively constant for different diets and methods of determination and seems not to be influenced significantly by the amount of loss and liveweight of pig. For practical purposes, and lacking evidence to the contrary, the composition can be considered to be constant and the following general composition (g per 160 g N) of essential amino acids is pro posed: lysine 30, methionine 10, cystine 16, threonine 45, tryptophan 12, isoleucine 25, leucine 40, histidine 15, phenylalanine 30, tyrosine 20, valine 35. The composition is, compared with ideal protein and most feedstuffs, characterized by a relatively low contribution of all essential amino acids, except threonine, cystine and tryptophan.

Biological and chemical evaluation of chick pea seed proteins as affected by germination, extraction and alpha-amylase treatment.

The effects of germination, extraction (double extraction with 70% ethanol and water at isoelectric point) and alpha-amylase treatments of chick pea seed flours on crude protein, total carbohydrate, protein efficiency ratio (PER), biological value (BV), true digestibility (TD), net protein utilization (NPU), essential amino acid composition, in-vitro protein digestibility (IVPD) and actual amino acid indices (essential amino acid index or amino acid score) were evaluated. Crude protein content was increased (8-149%), while total carbohydrate was decreased (11-62%) by germination, extraction and alpha-amylase treatments. Alpha-amylase treatment was more efficient in reducing total carbohydrate and increasing the protein content than that of extraction treatment. The protein quality of chick pea flours as measured by PER, BV, TD, NPU, IVPD and corrected amino acid indices (actual amino acid indices x IVPD) was significantly improved by these treatments. The protein quality of germinated-alpha-amylase treatment was comparable with casein, while germinated-alpha-amylase treaded seeds appeared nutritionally superior to casein. The results indicate that the germinated-alpha-amylase and germinated-alpha-amylase-extracted treatments could be used successfully as a source of concentrated high quality protein for baby food production. The corrected amino acid indices gave better prediction of PER, BV, TD and NPU (r = 93 to 97) than actual amino acid indices (r = 45 to 71). PER was highly correlated with corrected amino acid score (r = 0.93). The PER could be predicted from the following simple regression equation: PER = -1.827 + 0.0561 x corrected amino acid score.

Rebalancing essential amino acids intake by self-selection in the rat.

The purpose of the present study was to assess whether rats are capable of selecting the right proportions of two diets that are individually inappropriate in terms of essential amino acid composition to satisfy their amino acid requirements. Rats were offered a choice of one protein-free regimen and another devoid of only one essential amino acid (either threonine or isoleucine) set up in such a way as to provide amino acid balance if they were consumed in 1/3 and 2/3 proportions respectively. Preliminary experiments had established that all our diets were aversive by themselves except for the 60 g casein/kg diet. Rats did reach almost the necessary proportion with, according to published standards (National Research Council, 1978), some excess in isoleucine intake. In addition, given access to two aversive diets that were each nutritionally inadequate, rats showed no aversion and gained body weight when they had the opportunity to consume both of them. Beyond the capacity that rats have of rebalancing their micronutrient intake, the present experiment brings out the idea that the imbalance-induced aversion:preference ratio may be completely upset when this omnivore has access to more than one feed.

Effects of Dietary Energy: Protein Ratio and Stocking Density on Growth and Survival of the Common Snapping Turtle Chelydra serpentinal1

AbstractAlthough the common snapping turtle Chelydra serpentina is cultured commercially in the United States, little information is available on nutritional and culture requirements. This study was conducted to evaluate the effects of dietary energy: protein ratio and stocking density on survival, growth, feed consumption, feed conversion, liposomatic index, dress‐out percentage, and productive protein value of cultured, common snapping turtles. Hatchling turtles were stocked at 29 and 58 animals/m2 and fed one of seven prepared diets. Six diets contained 30, 35, or 40% protein at two digestible energy (DE) levels (7 or 9 kcal DE/g protein); the seventh was a reference diet (66% protein and 5 kcal DE/g protein) formulated to equal or exceed the whole‐body essential amino acid composition of wild, common snapping turtles. Turtles stocked at 58/m2 exhibited greater mortality, lower weight gain, higher feed consumption, less‐efficient feed conversion, lower liposomatic index, and lower productive protein value than turtles stocked at 29/m2 (P &lt; 0.05). The reference diet produced the greatest weight gain (P &lt; 0.001). The superior performance of turtles fed the reference diet suggests that: 1) the protein (amino acid) content and/or energy: protein ratio of the reference diet was superior to that of the other diets tested; 2) improvements in growth parameters can be made with dietary manipulation; and 3) high levels of plant protein can be used in prepared, snapping turtle diets.

Preparation and characteristics of coprecipitate proteins from oilseeds and legumes seeds

AbstractThe chemical composition as well as functional and nutritional properties of the coprecipitated proteins from a mixture of legumes and oilseeds sources and of the protein isolates of each vegetable source were studied. The results indicated that the protein coprecipitates of the vegetable sources blends show higher nutritional values, better functional properties, lower levels of antinutritional factors, better in vitro protein digestibility and better composition of essential amino acids than those of their individual protein isolates.

Amino Acid Composition of the Ovaries, Muscle, and Whole Body of Yellow Perch

Abstract The amino acid (AA) compositions of ovaries, whole body, and muscle of yellow perch (Perca flavescens) collected in November differed significantly (P < 0.05). Levels of alanine, arginine, glycine, histidine, hydroxyproline, lysine, methionine, and proline were greater in whole fish than in ovaries. Levels of alanine, glycine, hydroxyproline, and proline were greater in whole fish than in muscle. Levels of alanine, phenylalanine, proline, serine threonine, and valine were higher in ovaries than muscle. No differences were found in the essential amino acid (EAA) composition of whole 14-g, 78-g, or 130-g yellow perch or in the AA composition of ovaries from 171-g wild and 8l-g laboratory-raised yellow perch. The EAA profile ofwhole yellow perch closely resembled those of whole rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus). Differences in muscle and ovary profiles were evident between yellow perch and other freshwater fishes. Until the amino acid requirements of yellow perch are established empirically, we recommend that production feeds be formulated in accordance with muscle AA profiles, modified for brood stock in recognition of ovarian EAA composition.

In vitro maturation, fertilisation and culture of bovine oocytes in a modified Ménézo B2 medium

In this study we investigated the influence of essential amino acid composition of the medium on in vitro maturation and culture of bovine oocytes (cleavage of oocytes and development capacity of embryos). Oocytes were matured and cultured in vitro in a modified Ménézo B2 medium (MMM). The medium was modified by adding amino acids, not as single compounds, but as amino acid supplements for MEM (Minimum Essential Medium) or BME (Basal Medium Eagle) tissue culture medium, which differ completely in their content of essential amino acids. In the medium with MEM supplements the content of all essential amino acids except glutamine is at least twice as high as in the BME-supplemented medium. Oocytes were randomly allocated to one of four treatments: (1) in vitro maturation (IVM) and in vitro culture (IVC) in MMM with MEM amino acids (MEM medium); (2) IVM in MEM medium, IVC in MMM with BME supplements (BME medium); (3) IVM in BME medium, IVC in MEM medium; (4) IVM and IVC in BME medium. After IVM in MEM medium, more cumulus-oocyte complexes displayed marked expansion of the cumulus cells and cleavage occurred more frequently than after IVM in BME medium. More oocytes underwent cleavage when cultured in MEM medium than in BME medium. A higher number of embryos entered the compact morula or blastocyst stage when cultured in BME medium. Development to the blastocyst stage occurred faster after IVM and IVC in BME medium than in the other groups. The results demonstrate that the content of essential amino acids of the maturation and culture medium affects the development of bovine embryos in vitro.

Utilization of Malt Protein Flour in Fingerling Rainbow Trout Diets

Two feeding experiments were conducted to evaluate malt protein flour (MPF) as an alternative protein source for the diet of rainbow trout Oncorhynchus mykiss fingerlings. MPF is a new protein rich by-product from brewer's spent grain. Experiment 1 was conducted to clarify the suitable substitution level of MPF for white fish meal (WFM) in the diet. The control diet, containing WFM as the sole protein source, and isonitrogenous (40% crude protein) experimental diets, containing MPF substituted for 20 to 80% of WFM protein, were fed to fish with an average initial weight of 10g for 6 weeks. Weight gain and feed efficiency in fish fed the diet substituting MPF up to the 60% level were not different (p>0.05) from those in fish fed the control diet. There were no significant differences in protein and energy retention between 0 to 40% substitution level. In Experiment 2, crystalline essential amino acids (EAA) were supplemented in the diets containing MPF to simulate the EAA composition in the control diet. Consequently, no significant differences were detected in protein and energy retention between 0 to 60% substitution level. Thus, these results suggest that MPF is a promising alternative protein source for the diet of fingerling rainbow trout.

Predicting amino acid adequacy of diets fed to Holstein steers.

The Cornell Net Carbohydrate and Protein System (CNCPS) and NRC (1985) models were evaluated for accuracy in predicting metabolizable protein (MP) and essential amino acid (EAA) allowable ADG, using chemical body and feed composition data from feeding trials with Holstein steers. Nine Holstein steers (113 to 200 kg) were slaughtered and determined to have the following whole-body essential amino acid composition of (grams/100 grams of protein): arginine, 5.94; histidine, 2.07; isoleucine, 2.28; leucine, 5.72; lysine, 5.81; methionine, 1.99; phenylalanine, 3.04; threonine, 3.52; tryptophan, .57; and valine, 3.32. The NRC and CNCPS were then tested against data from 25 feeding periods, each representing the 56-d growth of 10 Holstein steers (mean BW of 162 kg), to determine their ability to predict the gain allowed by the supply of MP and the first-limiting EAA. The NRC (1985) system accounted for 46% of the variation in MP allowable gain, with an average bias of -30%. The CNCPS accounted for 87 and 73% of the variation in MP and EAA allowable gain, with a bias of 8 and 5%, respectively. The bias was reduced to 3% (R2 of .82) when ADG was predicted by the factor (ME, MP, or EAA) first-limiting ADG.

Effects of level of inclusion of copra meal in balanced diets supplemented with synthetic amino acids on growth and fat deposition and composition in growing pigs fed ad libitum at a constant temperature of 25 °C

Pigs, 32 male and 32 female housed at a constant temperature of 25 °C were fed, ad libitum over the liveweight range 25–55 kg, diets containing 0, 100, 200 and 300 g kg −1 of copra meal which were balanced for their essential amino acid compositions. Inclusion of 100 g kg −1 copra meal resulted in slightly poorer growth rates compared with the control diet, but no further deterioration was observed up to 300 g kg −1 ( P = 0.044). Increasing copra meal content of the diet was associated with a progressive reduction ( P = 0.017) in the voluntary feed intakes of the animals, although feed conversion ratio was unaffected by dietary treatment. With increasing inclusion of copra meal, backfat thickness decreased at points P 2 ( P = 0.018) and P 1 + P 3 ( P = 0.017). Increasing level of inclusion of copra meal was associated with increases ( P < 0.001) in levels of lauric acid (C12:0) and myristic acid (C14:0) and decreases ( P < 0.001) in stearic acid (C18:0) and linoleic acid (C18:2) in the bsckfat. Thsse changes reflected, to varying degrees, changes in the fatty acid composition of the dietary oil as the proportion of coconut oil in the diet was increased.