Soressa M. Kitessa

Utilisation of fish oil in ruminants

Abstract A study was conducted to determine the transfer of eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6) from fish oil into goats’ milk. Goats were sequentially offered three diets: control (C) pellets (lucerne hay-oat grain: 60/40 w/w), C plus tuna oil protected against ruminal biohydrogenation (PTO pellets), and C plus unprotected tuna oil (UTO pellets). In supplemented diets, tuna oil constituted 3% of total dry matter (DM), and each supplement was fed for 7 days, with 12 days allowed between the two fish oil feeding periods to minimise carry-over effects. Dry matter intake, milk yield, protein and fat yield were reduced by feeding UTO, but not PTO, pellets. Goats produced ω-3 enriched milk (0.3–0.5% EPA and 1.01–1.12% DHA) when fed either supplement. The rate of transfer of dietary EPA and DHA to milk ranged from 3.5 to 7.6%. Significant transfer of EPA and DHA from tuna oil into goat milk, without deleterious effects on intake or milk yield is possible, provided that the oil supplement is substantially protected against ruminal biohydrogenation.

Protection of conjugated linoleic acids from ruminal hydrogenation and their incorporation into milk fat

In vitro incubations were used to assess the hydrogenation of conjugated linoleic acid (CLA) isomers 9-cis 11-trans and 10-trans 12-cis present in synthetically produced CLA-60. About 80‐ 90% of the unprotected CLA was hydrogenated when incubated at 388C for 24 h anaerobically with sheep rumen fluid, the main end product of hydrogenation being trans-octadecaenoic acid (C18:1). Encapsulation of the CLA in a matrix of protein provided a protection of about 70% with a 30% hydrogenation of the CLA isomers, resulting in no significant change in the trans-C18:1 but an increase in the level of stearic acid (C18:0). Feeding sheep with unprotected CLA or protected CLA increased the proportion of isomers 9-cis 11-trans and 10-trans 12-cis in abomasal digesta. The concentration of the CLA isomers leaving the abomasum and available for absorption at the small intestine was about 3.5‐4% higher for the protected CLA, confirming protection imparted by encapsulation. Feeding lactating goats with protected CLA increased the proportion of isomers 9-cis 11-trans and 10-trans 12-cis in milk fat. The total CLA levels were enhanced by about 10-fold above the control levels present in milk fat with an efficiency of transfer into milk fat of 36‐41% and 21‐30%, respectively, for the two isomers. # 2000 Published by Elsevier Science B.V.

Preliminary estimates of genetic parameters for carcass and meat quality traits in Australian sheep.

Using performance from progeny born in 2007 and 2008 generated by theInformation Nucleus program of the Cooperative Research Centre for Sheep Industry Innovation, preliminary estimates of heritability were obtained for a rangeofnovelcarcassandmeatattributesoflambrelevanttoconsumers,includingcarcasscharacteristics,meatqualityand nutritionalvalueoflamb.Phenotypicandgeneticcorrelationsofliveanimaltraitswithcarcasscompositionandmeatquality traits were also estimated. The data were from progeny located at eight sites, sired by 183 rams from Merino, maternal and terminalmeatbreedsandwererepresentative oftheMerino,BorderLeicester ·Merino,Terminal ·MerinoandTerminal · Border Leicester-Merino production types of the Australian sheep industry. Data were available from 7176 lambs for weaning weight, 6771 lambs for ultrasound scanning and 4110 lambs for slaughter traits. For the novel meat quality traits, generally moderate to high heritability estimates were obtained for meat quality measures of shear force (0.27 aged 1 day, 0.38 aged 5 days), intramuscular fat (0.39), retail meat colour (range of 0.09 to 0.44) and myoglobin content (0.22). The nutritional value traits of omega-3 fatty acids and iron and zinc contents tended to have low to moderate heritabilities (0.11-0.37), although these were based on fewer records. Fresh meat colour traits were of low to moderate heritability (0.06-0.21)whereasmeasuresofmeatpHwereoflowheritability(~0.10).Forthecarcasstraits,estimatesofheritabilitywere moderate to high for the various measures of carcass fat (0.18-0.50), muscle weight (0.22-0.35), meat yield (0.24-0.35), carcassmuscledimensions(0.25-0.34)andboneweight(0.27).Resultsindicatethatformostlambcarcassandmeatquality traits there is sufficient genetic variation for selection to alter successfully these characteristics. Additionally, most genetic correlations of live animal assessments of bodyweight, muscle and subcutaneousfat with the carcass and meat quality traits werefavourable.Appropriatedefinitionofbreedingobjectivesanddesignofselectionindexesshouldbeabletoaccountfor the small unfavourable relationships that exist and achieve the desired outcomes from breeding programs.

Influence of finishing systems and sampling site on fatty acid composition and retail shelf-life of lamb

Thirty 7-month-old crossbred lambs (Poll Dorset × Border Leicester × Merino) finished over 5 weeks on either low quality pasture or grain-with-hay on a farm in southern Victoria were assessed for carcass parameters, muscle fat composition and retail colour stability. Lambs on the grain diet had a mix of barley grain (80%) and lentils (20%) at 800 g/head.day (air-dry basis ~ad libitum) with cape weed (Arctotheca calendula) hay available at all times. Lambs under grazing had predominantly rye grass (Lolium perenne) and barley grass (Hordeum leporinum) available ad libitum. Carcass weight tended to be higher (P = 0.14) in grain-fed lambs than in grass-fed lambs, but fatness indicated by GR (total muscle + fat tissue thickness at 11 cm from midline) did not differ between feeding systems. Fatty acid composition was determined in the loin from the forequarter (M. longissimus thoracis) and lumbar (M. longissimus lumborum) regions and from the leg region (M. semimembranosus). This showed that grain-finished lamb had higher muscle fat (P 0.05) between feeding groups. Saturated fatty acids were greater (P < 0.01) in both loin sampling sites than the leg. The levels of EPA, docosahexaenoic acid and docosapentaenoic acid were lower (P < 0.01) in the forequarter (9%) or lumbar (11%) sites than the leg sampling site. The distribution pattern of fatty acids across the three sampling sites did not differ between feed types. Retail colour stability determined over 4 days of display (only performed in muscle from the lumbar site), evaluated by the redness (HunterLab a*-value) and metmyoglobin formation (reflectance ratio at 630 : 580-nm wavelengths) was superior for grass-fed lamb compared with short-term grain-finished lamb. The results demonstrate that the health claimable omega-3 fat mainly EPA or total omega-3 fat content in lamb was not altered by short-term grain finishing compared with lamb finished under pasture grazing conditions.

DHA-Containing Oilseed: A Timely Solution for the Sustainability Issues Surrounding Fish Oil Sources of the Health-Benefitting Long-Chain Omega-3 Oils

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA.

Echium oil is better than rapeseed oil in enriching poultry meat with n-3 polyunsaturated fatty acids, including eicosapentaenoic acid and docosapentaenoic acid.

alpha-Linolenic acid (ALA; 18 : 3n-3) and stearidonic acid (SDA; 18 : 4n-3) are on the biosynthetic pathway of EPA (20 : 5n-3) and DHA (22 : 6n-3). The n-3 fatty acid in rapeseed oil is ALA while Echium oil contains both ALA and SDA. To determine the comparative efficacy of ALA- and SDA-rich oils in enriching broiler meat with n-3 PUFA, we offered diets supplemented with rapeseed oil (rapeseed group) or Echium oil (Echium group) for 35 d to two groups of chicks (age 21 d). There were no differences in carcass weight (2.20 (sem 0.06) v. 2.23 (sem 0.05) kg), boned, skinless thigh muscle (494 (sem 20.5) v. 507 (sem 16.7) g), boned, skinless breast muscle (553 (sem 13.4) v. 546 (sem 11.6) g) or organ weights (heart, liver and gizzard) between the two groups. The total intramuscular fat (IMF) percentage of thigh (8.0 (sem 0.64) v. 8.1 (sem 0.62) %) and breast muscles (2.3 (sem 0.24) v. 2.0 (sem 0.19) %) were also similar between the groups. In contrast, the concentrations of most of the individual n-3 fatty acids (ALA, SDA, EPA and docosapentaenoic acid) were all higher in the Echium than the rapeseed group (P < 0.05). However, differences in DHA concentrations were significant in breast but not thigh muscle IMF. The total n-3 yields/100 g serve thigh muscle were 265 and 676 mg for the rapeseed and Echium groups, respectively (P < 0.0001). The corresponding values for equivalent breast muscles were 70 and 137 mg, respectively (P < 0.01). We conclude that Echium oil is a better lipid supplement than rapeseed oil in changing the concentration and yield of n-3 fatty acids, except DHA, in broiler meat.

Lipid-Induced Insulin Resistance in Skeletal Muscle: The Chase for the Culprit Goes from Total Intramuscular Fat to Lipid Intermediates, and Finally to Species of Lipid Intermediates

The skeletal muscle is the largest organ in the body. It plays a particularly pivotal role in glucose homeostasis, as it can account for up to 40% of the body and for up to 80%–90% of insulin-stimulated glucose disposal. Hence, insulin resistance (IR) in skeletal muscle has been a focus of much research and review. The fact that skeletal muscle IR precedes β-cell dysfunction makes it an ideal target for countering the diabetes epidemic. It is generally accepted that the accumulation of lipids in the skeletal muscle, due to dietary lipid oversupply, is closely linked with IR. Our understanding of this link between intramyocellular lipids (IMCL) and glycemic control has changed over the years. Initially, skeletal muscle IR was related to total IMCL. The inconsistencies in this explanation led to the discovery that particular lipid intermediates are more important than total IMCL. The two most commonly cited lipid intermediates for causing skeletal muscle IR are ceramides and diacylglycerol (DAG) in IMCL. Still, not all cases of IR and dysfunction in glycemic control have shown an increase in either or both of these lipids. In this review, we will summarise the latest research results that, using the lipidomics approach, have elucidated DAG and ceramide species that are involved in skeletal muscle IR in animal models and human subjects.

Commentary on a trial comparing krill oil versus fish oil

Considerable interest exists presently in comparing the performance of krill oil (KO) and fish oil (FO) supplements. Ramprasath et al. (Lipids Health Dis12: 178, 2013) have recently compared use of KO and FO in a trial with healthy individuals to examine which oil is more effective in increasing n-3 PUFA, decreasing the n-6:n-3 ratio and improving the omega-3 index. The authors concluded that KO was more effective than FO for all three criteria. However, careful examination of the fatty acid profiles of the oils used showed that the FO used was not a typical FO; it contained linoleic acid as the dominant fatty acid (32%) and an n-6:n-3 ratio of >1. Due to the fatty acid profile being non-representative of typically commercially marketed FO, the conclusions presented by Ramrasath et al. (Lipids Health Dis12: 178, 2013) are not justified and misleading. Considerable care is needed in ensuring that such comparative trials do not use inappropriate ingredients.

Mucin Gene mRNA Levels in Broilers Challenged with Eimeria and/or Clostridium perfringens

SUMMARY The effects of Eimeria (EM) and Clostridium perfringens (CP) challenges on the mRNA levels of genes involved in mucin (Muc) synthesis (Muc2, Muc5ac, Muc13, and trefoil family factor-2 [TFF2]), inflammation (tumor necrosis factor alpha [TNF-&agr;] and interleukin-18 [IL-18]), and metabolic processes (cluster of differentiation [CD]36) in the jejunum of broilers were investigated. Two parallel experiments involving 1) EM challenge and 2) EM and CP challenges were conducted. The first experiment was a 2 × 2 study with 12 birds per treatment (N  =  48) involving fishmeal substitution (25%) in the diet (FM) and EM challenge. The treatments were: Control (FM−, EM−), Fishmeal (FM+, EM−), EM challenge (FM−, EM+), and fishmeal substitution and EM challenge (FM+, EM+). The second experiment was a 2 × 2 × 2 experiment with six birds per treatment (N  =  48) involving fishmeal (FM−, FM+), Eimeria (EM−, EM+), and C. perfringens (CP−, CP+). In both arms of the study, male broilers were given a starter diet for the whole period of 16 days, except those assigned to FM+, where 25% of the starter ration was replaced with fishmeal from days 8 to 14. EM inoculation was performed on day 9 and CP inoculation on days 14 and 15. The EM challenge birds were euthanatized for sampling on day 13; postmortem examination and sampling for the Eimeria plus C. perfringens challenge arm of the study were on day 16. In the Eimeria challenge arm of the study, fishmeal supplementation significantly suppressed the mRNA levels of TNF-&agr;, TFF2, and IL-18 pre-CP inoculation but simultaneously increased the levels of Muc13 and CD36 mRNAs. Birds challenged with Eimeria exhibited increased mRNA levels of Muc13, Muc5ac, TNF-&agr;, and IL-18. In the Eimeria and C. perfringens challenge arm, birds exposed to EM challenge exhibited significantly lower mRNA levels of Muc2 and CD36. The mRNA levels of CD36 were also significantly suppressed by CP challenge. Our results showed that the transcription of mucin synthesis genes in the jejunum of broilers is modulated by fishmeal inclusion in the diet. Furthermore, we show for the first time suppression of CD36 mRNA levels in the intestine of broilers challenged with Eimeria or C. perfringens. RESUMEN Niveles de ARN mensajero de genes de la mucina en pollos desafiados con Eimeria y/o con Clostridium perfringens. Los efectos del desafíos por Eimeria (EM) y por Clostridium perfringens (CP) en los niveles de ARN mensajero de los genes implicados en la síntesis de la mucina (Muc2, Muc5ac, Muc13 y del factor 2 de la familia trefoil [TFF2]), en la inflamación (factor de necrosis tumoral alfa [TNF-&agr;] y la interleucina 18 [IL-18]) y de los procesos metabólicos (grupo de diferenciación [CD] 36) en el yeyuno de pollos de engorde fueron investigados. Se realizaron dos experimentos paralelos que implicaron 1) desafío con Eimeria y 2) desafíos con Eimeria y C. perfringens. El primer experimento fue un estudio de 2 × 2 con 12 aves por tratamiento (N  =  48) que implica la sustitución de la harina de pescado (25%) en la dieta (FM) y el desafío con Eimeria. Los tratamientos fueron: control (FM-, EM-), Harina de pescado (FM+, EM-), desafío con Eimeria (FM-, EM+) y la sustitución de la harina de pescado con desafío con Eimeria (FM+, EM+). El segundo experimento fue un experimento 2 × 2 × 2 con seis aves por tratamiento (N  =  48) que incluyó harina de pescado (FM, FM+), Eimeria (EM- EM+) y C. perfringens (CP-, CP+). En ambas partes del estudio, a los pollos machos se les dio una dieta de iniciación para todo el período de 16 días, excepto a los asignados al grupo FM+, donde se sustituyó el 25% de la ración de iniciación con harina de pescado de los días 8 a 14. El desafío con Eimeria se realizó al día 9 y la inoculación con C. perfringens se realizó en los días 14 y 15. Se les practicó la eutanasia a las aves desafiadas con Eimeria en el día 13 con fines de muestreo; el examen post mortem y el muestreo para la parte desafiada con Eimeria y C. perfringens fue en el día 16. En la parte del estudio con el desafío por Eimeria, la suplementación de la harina de pescado suprimió significativamente los niveles de ARN mensajero de TNF-&agr;, TFF2 y de IL-18 antes de la inoculación con C. perfringens pero a la vez aumentó los niveles de ARN mensajero de Muc13 y CD36. Las aves desafiadas con Eimeria exhibieron aumento de los niveles de ARN mensajero para Muc13, Muc5ac, TNF-&agr; y de IL-18. En la parte del desafío con Eimeria y C. perfringens, las aves expuestas al desafío con Eimeria mostraron niveles significativamente más bajos de ARN mensajero para Muc2 y CD36. Los niveles de ARN mensajero de CD36 también se suprimieron significativamente por el desafío con C. perfringens. Estos resultados muestran que la transcripción de genes de la síntesis de mucina en el yeyuno de pollos de engorde es modulada por la inclusión de harina de pescado en la dieta. Además, se muestra por primera vez la supresión de los niveles de ARN mensajero de CD36 en el intestino de los pollos de engorde desafiados con Eimeria o con C. perfringens.

New biomarkers for intestinal permeability induced by lipopolysaccharide in chickens

Intestinal health is influenced by a complex set of variables involving the intestinal microbiota, mucosal immunity, digestion and absorption of nutrients, intestinal permeability (IP) and intestinal integrity. An increase in IP increases bacterial or toxin translocation, activates the immune system and affects health. IP in chickens is reviewed in three sections. First, intestinal structure and permeability are discussed briefly. Second, the use of lipopolysaccharide (LPS) as a tool to increase IP is discussed in detail. LPS, a glycolipid found in the outer coat of mostly Gram-negative bacteria, has been reported to increase IP in rats, mice and pigs. Although LPS has been used in chickens for inducing systemic inflammation, information regarding LPS effects on IP is limited. This review proposes that LPS could be used as a means to increase IP in chickens. The final section focuses on potential biomarkers to measure IP, proposing that the sugar-recovery method may be optimal for application in chickens.