Conjugated linoleic acid changes swine performance and carcass composition

Conjugated linoleic acid (CLA) is a collective term for positional and geometric isomers of linoleic acid. Dietary CLA has been shown to improve feed efficiency, decrease body fat, and increase lean tissue in laboratory animals. We hypothesized that CLA would improve performance and carcass composition and would be deposited in pork tissues. Diets of 40 crossbred pigs were supplemented with CLA to determine its effects on performance and carcass composition. Eight replications of five littermate barrows with an initial average weight of 26.3 kg were allotted at random to individual pens. Within replication dietary treatments containing 0, 0.12, 0.25, 0.5, or 1.0% CLA were assigned at random. Pigs were weighed and feed disappearance was determined at 14-d intervals. Average daily gain increased linearly as the level of CLA increased in the diet (P < 0.05). Average daily feed intake was not affected by the concentration of CLA in the diet. Therefore, a linear increase in gain:feed ratio (P < 0.05) was observed. Carcasses from animals fed control diets had greater 10th rib backfat than carcasses from animals fed CLA (P < 0.05). Ultrasound measurement and carcass measurements showed less fat depth over the loin eye at the 10th rib of pigs fed doses of CLA (P < 0.05) than that observed for control pigs. Belly hardness (firmness) increased linearly as the concentration of CLA in the diet increased when bellies were measured for firmness either lean side up (P < 0.001) or lean side down (P < 0.05). Loin dissection data demonstrated that CLA produced a quadratic treatment effect both for less intermuscular fat (P < 0.001) and less subcutaneous fat (P < 0.05) and a linear increase for bone (P < 0.05), although finished loin weight only tended to increase (P = 0.08). The CLA concentration increased in a linear relationship in both subcutaneous fat (P < 0.001) and lean tissue (P < 0.001). Dietary CLA was incorporated into pig tissues and had positive effects on performance and body composition.     

Efficient screening of the cystinuria-related C663T Slc3a1 nonsense mutation in Newfoundland dogs by denaturing high-performance liquid chromatography.

Cystinuria in Newfoundland dogs is a metabolic disease associated with a nonsense mutation in the exon 2 of the Slc3a1 gene. Similar to type I human cystinuria, heterozygote carriers are not affected by the disease and do not reveal differences in urinary concentration of dibasic amino acids when compared with normal dogs. However, through a recessive mode of inheritance, these dogs are able to transmit the disease to their offspring. Early detection of mutation carriers through cost-effective reliable methods is therefore essential for the implementation of breeding methods aimed at the eradication of the disease. Denaturing high-performance liquid chromatography (DHPLC) is a recently developed technique for rapid and efficient screening of nucleotide polymorphisms in polymerase chain reaction-amplified products. This technique was used for the identification of the C663T Slc3a1 mutation in Portuguese Newfoundland dogs. Polymerase chain reaction products amplified from a region containing the C663T locus were subjected to DHPLC analysis, and results were double checked by DNA sequencing. Results showed the presence of the mutation in 6 of the 22 dogs tested. Urine biochemical parameters correlated well with the number of mutated Slc3a1 copies, and homozygotes for the C663T mutation were the only dogs diagnosed with cystinuria. Sequence analysis confirmed the DHPLC results, demonstrating that the technique could be a reliable alternative to sequencing for the rapid and cost-effective identification of mutations in canine breeds.     

Evaluation of Quality Factors in Argentine Maize Races

Samples of Argentine maize from 12 landraces were analyzed for starch and amylose content and were evaluated for hardness parameters. Amylose contents of these Argentine landraces were generally higher than for typical dent hybrids grown in the United States. Hardness, as estimated by near‐infrared reflectance; from wavelength shift of the near‐infrared transmittance spectrum absorbance maximum (λ_max) in the 610–680 nm region; and by percentage of γ‐zein in zein‐2 (determined by reversed‐phase HPLC), correlated well with classical definitions of endosperm type and with amylose content. Starch content correlated negatively with hardness. Flint landraces varied substantially in amylose and starch content. The strong correlation between amylose content and maize endosperm hardness confirms and strengthens previous observations, and may provide a compositional basis for endosperm quality.     

Effect of Clay Minerals and Organic Matter on the Cation Exchange Capacity of Silt Fractions

The cation exchange capacity (CEC) and specific surface properties were investigated in four particle‐size fractions < 50 μm from three loess (one Kastanozem and two Phaeozems), a holocene (Fluvisol) and a basalt soil (Nitisol) before and after destruction of organic matter. Particle‐size fractions were separated by sedimentation after chemical and physical dispersion of the soil samples. Illite, amorphous minerals, mixed layers, smectite and kaolinite were the predominant clay minerals. They were detected in all size fractions. The CEC increased with increasing organic matter contents and this effect was more pronounced in coarser fractions. The organic matter content per unit surface area was two or three times larger in coarse silt than in clay, irrespective of the soil type.     

Development of sensory organs and changes of behavior in larvae of the sutchi catfish, <Emphasis Type="Italic">Pangasianodon hypophthalmus</Emphasis>

Larvae of the sutchi catfish Pangasianodon hypophthalmus hatch with morphologically immature features, but sensory organs develop rapidly as the fish grow. By 1 day old, yolk-sac larvae showed notochord flexion, and by 2 days old larvae were observed to have consumed a large part of the yolk sac. At this stage, larvae had well-developed eyes, olfactory organs with ciliated receptor cells, inner ears with semicircular canals, and numerous taste buds, and they commenced ingestion of rotifers, Artemia nauplii, and artificial compound feed. Two-day-old larvae had many free neuromasts on the surface of the head and flanks and clearly showed rheotaxis. By 20 days old, free neuromasts in postflexion larvae had sunk under the skin. At this later stage, larvae swam against a water current and schooled along the side of the fish tank. Rapid development of sensory organs and notochord flexion would be an adaptation for survival in conditions of flowing water, as in the Mekong River. In this study, we show that development of the lateral line in the postflexion stage seems to be closely related to larval behavior, suggesting that these developments could be essential for sutchi catfish larvae survival.     

The economic potential for stabilizing the price and supply of a basic foodstuff: The case for potato storage in Ecuador

American Journal of Potato Research - This article presents an economic feasibility study of storage potential for stabilizing potato prices and/or supplies in Ecuador, where the high potato price...     

Reproductive divergence between growth forms of Lake Winnipeg walleye (Sander vitreus)

Moles MD, Johnston TA, Robinson BW, Bernard AM, Wilson CC, Wiegand MD, Leggett WC. Reproductive divergence between growth forms of Lake Winnipeg walleye (Sander vitreus).
Ecology of Freshwater Fish 2011: 20: 52–66. © 2010 John Wiley & Sons A/S Abstract – Growth polymorphisms occur in many fish species, particularly in northern temperate freshwater lakes. The only known growth polymorphism in walleye (Sander vitreus) is in Lake Winnipeg, Canada, where slow‐growing (dwarf) and fast‐growing (normal) morphotypes co‐exist. We examined differences in reproductive traits between forms to determine whether divergence in growth rates was accompanied by divergence in reproductive strategies and also assessed the genetic composition of both forms using mitochondrial and microsatellite DNA to determine their origin and potential reproductive isolation. Both sexes of the dwarf form produced relatively larger gonads than the normal form. Female dwarfs also had a lower liver lipid concentration, a higher ovary lipid concentration, and produced relatively larger eggs compared to the normal form. There was also some indication that dwarf and normal females differed in the fatty acid profiles of their egg lipids. Population genetic analysis based on partial sequencing of the mitochondrial control region and genotyping nine microsatellite loci indicated a single interbreeding population and sympatric origin for both morphotypes. The dwarf form appears to make a relatively larger reproductive investment at a given body size, and the differences between the two forms may result from plastic developmental responses to subtle differences in niche use.     

Immune response and blood chemistry of pigs fed conjugated linoleic acid

Immune function (response to concanavalin A, cytokine production, and lymphocyte profiles) and blood chemistry variables were measured in growing-finishing pigs (Yorkshire/Landrace/Duroc dam × Hampshire sire) fed varying percentages of CLA (0, 0.12, 0.25, 0.50, and 1.0%). Blood was collected at 0, 14, 28, 42, and 56 d on feed (DOF). Total white blood cell (WBC) count increased (P < 0.01) linearly to 42 DOF. No differences (P = 0.53) were observed for WBC across CLA treatment. Nitric oxide was greater (P < 0.01) for the 1.0% CLA treatment compared with all other treatments. Flow cytometry using fluorescent labeled monoclonal antibodies to the CD4, CD8, double-positive CD4/CD8, and CD2 surface markers was used to determine lymphocyte subpopulations. Supplementation of CLA had no effect (P = 0.61) on lymphocyte subpopulation cell distribution. Most blood chemistry variables were within the normal metabolic range for pigs. A decrease was observed over DOF for P (P < 0.01) and K (P < 0.05). Additionally, Na and Cl concentrations increased (P < 0.05) from 14 to 28 DOF and decreased over the remainder of the trial. Electrolyte balance was not different (P = 0.38) across CLA treatments and was likely explained by no differences in feed intake among the CLA treatment groups. Blood lipid variables indicated that total cholesterol (P < 0.001), triglycerides (P < 0.001), high-density lipoproteins (P < 0.001), and low-density lipoproteins (P < 0.01) increased as the amount of CLA in the diet increased, but none of the results from these treatments exceeded the normal range of acceptability. These results suggested that CLA was safe when fed to growing-finishing pigs and had little effect on their immune function and blood chemistry variables.