RAB7A phosphorylation by TBK1 promotes mitophagy via the PINK-PARKIN pathway.

Removal of damaged mitochondria is orchestrated by a pathway involving the PINK1 kinase and the PARKIN ubiquitin ligase. Ubiquitin chains assembled by PARKIN on the mitochondrial outer membrane recruit autophagy cargo receptors in complexes with TBK1 protein kinase. While TBK1 is known to phosphorylate cargo receptors to promote ubiquitin binding, it is unknown whether TBK1 phosphorylates other proteins to promote mitophagy. Using global quantitative proteomics, we identified S72 in RAB7A, a RAB previously linked with mitophagy, as a dynamic target of TBK1 upon mitochondrial depolarization. TBK1 directly phosphorylates RAB7AS72, but not several other RABs known to be phosphorylated on the homologous residue by LRRK2, in vitro, and this modification requires PARKIN activity in vivo. Interaction proteomics using nonphosphorylatable and phosphomimetic RAB7A mutants revealed loss of association of RAB7AS72E with RAB GDP dissociation inhibitor and increased association with the DENN domain-containing heterodimer FLCN-FNIP1. FLCN-FNIP1 is recruited to damaged mitochondria, and this process is inhibited in cells expressing RAB7AS72A. Moreover, nonphosphorylatable RAB7A failed to support efficient mitophagy, as well as recruitment of ATG9A-positive vesicles to damaged mitochondria. These data reveal a novel function for TBK1 in mitophagy, which parallels that of LRRK2-mediated phosphorylation of the homologous site in distinct RABs to control membrane trafficking.

Evaluation of sulphur amino acid requirement of male Korean native ducklings from hatch to 21 day of age.

1. A dose-response experiment was conducted with male Korean native ducklings (KND) to evaluate the total sulphur amino acid (TSAA) requirement from hatch to 21 d of age. 2. A completely randomised design with 7 dietary TSAA concentrations (0.62%, 0.65%, 0.68%, 0.71%, 0.74%, 0.77% and 0.80%) were used with 6 replications per treatment. 3. Body weight (BW) and feed intake were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). One duckling per pen (n = 6) was killed by cervical dislocation to weigh empty body and drumsticks at the conclusion of experiment. 4. BW was improved significantly with increasing TSAA content, in a non-linear manner. A significant decrease of FCR was shown with increasing TSAA contents. TSAA requirement was determined by taking a mean value after fitting the data to both a linear-plateau and a quadratic-plateau model. Estimated TSAA requirements were 0.70%, 0.70%, 0.66% and 0.70% for the maximum BW, ADG and ADFI and for the minimum FCR, respectively. Increasing TSAA content improved quantity of full body weight (FBW), empty body weight (EBW) and drumstick weight (DSW), but there was no effect on proportion of DSW in relation to EBW and proportion of EBW to FBW. 5. In conclusion, the growth of male KND during 1 to 21 d of age was improved with increasing TSAA content, suggesting optimal TSAA requirements estimated by two analysis models.

The apparent metabolizable energy requirement of male Korean native ducklings from hatch to 21 days of age.

A study was conducted to determine the apparent metabolizable energy (AME) requirement of Korean native ducklings for hatch to 21 d of age. A total of 336 one-day-old male Korean native ducklings were used in a completely randomized design having 8 dietary treatments to provide a range of AME content from 2,600 to 3,300 kcal/kg (i.e., 100 kcal/kg disparity). Eight experimental diets containing varying levels of AME were formulated to meet the NRC (1994) nutrient specifications. Ducklings were randomly allocated to 48 pens (6 replicates per treatment and 7 ducklings per pen) and were offered their respective diets on an ad libitum basis for the period of study. Body weight and feed intake were measured weekly to calculate feed conversion ratio, energy intake, and protein intake. Two ducklings per pen (n = 6) were euthanized via cervical dislocation to weigh empty body and drumsticks at the conclusion of the experiment. Data were fitted to both linear-plateau and quadratic-plateau models for estimation of the AME requirements for Korean native ducklings for hatch to 21 d of age. The estimated AME requirements were 2,953, 3,007, and 2,950 kcal AME/kg diet for maximum daily gain, daily feed intake, and for minimum feed conversion ratio, respectively.

Net energy content of dry extruded-expelled soybean meal fed with or without enzyme supplementation to growing pigs as determined by indirect calorimetry.

Two experiments were conducted to determine the NE content of dry extruded-expelled soybean (DESBM) and the effect of a multienzyme carbohydrase (MC) mixture on the NE content of DESBM and to determine the effect of diet design on NE values in growing pigs using indirect calorimetry (IC). In Exp. 1, 24 barrows (19.6 ± 0.51 kg BW) were allotted in a completely randomized design to 4 dietary treatments: a corn­soybean meal basal diet (Diet A), a diet containing Diet A and DESBM in an 80:20 ratio with a constant CP (Diet B), a diet with an 80:20 ratio of Diet A and DESBM with a constant corn:soybean meal ratio (Diet C), and a diet with simple substitution of Diet A with DESBM in an 80:20 ratio (Diet D). Pigs were fed in metabolism crates for a period of 16 d to determine the DE and ME and thereafter were moved into an indirect calorimeter where O2 consumption and CO2 production were measured to determine heat production and fasting heat production. The NE content of DESBM was calculated (difference method) to be 2,632, 2,548 and 2,540 kcal/kg DM in diets B, C, and D, respectively. Respective values obtained with published prediction equations were 2,624, 2,530 and 2,436 kcal/kg. In Exp. 2, 24 barrows (16.9 ± 0.76 kg BW) were randomly allotted to 1 of 4 treatments. The diets were a corn­soybean meal basal diet and a diet containing the basal diet and DESBM in an 80:20 ratio with a constant corn:soybean meal ratio with or without 2 levels (0.05% and 0.1%) of MC. The experimental procedures were similar to those described in Exp. 1. Enzyme supplementation improved (P < 0.0001) the DE, ME, and NE content of the DESBM. Multienzyme carbohydrase at 0.05% and 0.1% of the diet improved NE values of DESBM by 4.9% and 3.7%, respectively. In conclusion, the NE values of DESBM obtained with the IC method were higher than the values obtained with prediction equations; the disparity was least when diets were formulated with a constant CP level. However, as the difference method was used to determine the NE of ingredient, it is more appropriate to maintain a constant ratio between the ingredients. Also, the NE value of DESBM obtained for diets C and D were not different. Hence, the average NE value of DESBM evaluated was 2,544 kcal/kg DM. Enzyme supplementation improved the NE content of DESBM fed to growing pigs.

True and standardized total tract phosphorus digestibility in canola meals from Brassica napus black and Brassica juncea yellow fed to growing pigs.

The aim was to determine the true total tract digestibility (TTTD) and standardized total tract digestibility (STTD) of P in canola meals from Brassica napus black (BNB) and Brassica juncea yellow (BJY) fed to growing pigs. Fifty-four barrows with an initial BW of 19.9 ± 0.22 kg (mean ± SEM) were allocated in 3 consecutive blocks to 1 of 9 dietary treatments in a randomized complete block design to give 6 replicate pigs per diet. Dietary treatments were cornstarch based with increasing concentrations of P, that is, 0.8, 1.6, 2.4, and 3.3 g/kg (as-fed basis) from either BNB or BJY as the sole source of P and a gelatin-based P-free diet. Limestone was added to maintain a Ca:total P ratio of 1.2:1 in all diets. All diets contained titanium dioxide (3 g/kg) as an indigestible marker. Daily feed allowance was calculated to supply 2.6 times the maintenance energy requirement based on the BW at the beginning of each period and offered in 2 equal portions at 0800 and 1600 h as a dry mash. Pigs were individually housed in metabolism crates and fed experimental diets for 16 d, including 9 d for adaptation to feed and 5 d for total but separate collection of feces and urine. The apparent total tract digestibility values of P increased from 19.0 to 30.0% for BNB and from 17.3 to 28.3% for BJY as the dietary P content increased from 0.8 to 3.3 g/kg DM. The TTTD of P was determined using the regression analysis as dietary P content increased from 0.8 to 3.3 g/kg whereas the STTD of P was calculated for the diet with the highest P content (i.e., 3.3 g/kg, as-fed basis) using the P-free diet to estimate endogenous P losses (EPL). The total and basal EPL estimates obtained with regression analysis and the P-free diet were 665 ± 0.03 and 209 ± 96 mg/kg DMI, respectively. The TTTD of P was 33.3 and 32.0% in BNB and BJY, respectively. Respective STTD values were 31.0 and 28.3%. The results indicated that the TTTD and STTD of P were comparable in the 2 canola meals from BNB and BJY canola.

Nutrient digestibility and growth performance of pigs fed diets with different levels of canola meal from Brassica napus black and Brassica juncea yellow.

Nutrient digestibility and the effect of high dietary inclusion of canola meals from Brassica napus black (BNB) and Brassica juncea yellow (BJY) on growing and weaned pigs performance were determined. In Exp.1, 6 ileal cannulated barrows (initial BW = 20.7 ± 1.5 kg) were used to determine the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in BNB and BJY. Pigs were allotted to diets containing either BNB or BJY as the sole source of protein in a crossover design to give 6 replicates per diet. The SID of all AA in BNB and BJY were similar. In Exp. 2, 168 weaned pigs (initial BW = 7.61 ± 0.76 kg) were assigned in a randomized complete block design to 7 diets (n = 24) consisting of a wheat-soybean meal-based control diet and 6 diets containing 5, 10 or 15% of canola meal derived from either BNB or BJY to determine the effect of different dietary inclusion on growth performance over a 28-d period postweaning. Diets were formulated to contain similar NE and SID of Lys. There were no differences in growth performance among treatments. In Exp. 3, 162 weaned pigs (initial BW = 7.26 ± 0.70 kg) were used to determine the effect of high BNB and BJY inclusion level without or with multicarbohydrase supplementation on growth performance and apparent total tract digestibility (ATTD) of CP, DM, and GE. A wheat-soybean meal-based control diet and 8 diets containing 20 and 25% of either BNB or BJY without or with added multi-carbohydrase were formulated (n = 18) to contain comparable NE and similar SID of Lys contents. Feeding the diets containing 25% of BNB or BJY supported similar growth performance as those containing 20%. The multi-carbohydrase had no effect on growth performance but improved (P < 0.05) the ATTD of DM, CP, and GE compared with those fed nonsupplemented diets irrespective of canola meal type. Diets containing 25% canola meal had lower (P < 0.05) ATTD of DM, CP, and GE regardless of canola meal type compared with the 20% canola meal diets. There was an interaction (P < 0.05) between canola meal type and inclusion level on ATTD of DM in which ATTD of DM decreased with increasing inclusion of both canola meal types. Results of the current study indicate that both BNB and BJY can be included up to 25% in weaned pig diets without compromising performance as long as the diets are formulated on an NE and SID of Lys basis. Also, enzyme addition improved the ATTD of CP, DM, and GE in weaned pigs in both BNB and BJY diets.

Feeding a diet containing resistant potato starch influences gastrointestinal tract traits and growth performance of weaned pigs.

The aim was to evaluate the effects of feeding resistant potato starch (RPS) as a natural source of resistant starch to weaned pigs for 28 d immediately after weaning. Sixty piglets (Yorkshire-Landrace × Duroc) weaned at 21 ± 2 d (1:1 male:female) with an initial BW of 7.2 ± 0.78 kg were assigned in a completely randomized design to 1 of 5 dietary treatments to give 6 observations per treatment and 2 pigs per pen. Dietary treatments consisted of a negative control corn-soybean meal-wheat-wheat middlings-based diet (NC; no antimicrobial agents added) or the NC supplemented with RPS either as powder or in capsules and each included at 0.5 or 1.0% as a top-dressing on each day. Diets were formulated to meet 1998 NRC specifications. Pigs were offered the experimental diets on an ad libitum basis for 28 d and water was available at all times. The ADG, ADFI, and G:F were determined weekly. Fecal score was determined daily for 14 d after weaning. At the conclusion of study, 1 pig from each pen was randomly selected and euthanized (n = 6 per treatment) to determine visceral organ weight, digesta pH, VFA, and ammonia N (NH3-N) concentrations. Resistant potato starch supplementation improved (P < 0.001) fecal score, and pigs offered 1.0% RPS had more solid feces (P < 0.05) than those offered 0.5% RPS during the first 14 d after weaning, independent of the form of RPS. Resistant potato starch supplementation decreased (P < 0.05) ileal and cecal digesta pH regardless of the levels of RPS or mode of delivery. The total VFA concentrations in cecal digesta were greater (P < 0.05) but the molar proportion of branched-chain fatty acids were lower (P < 0.05) for pigs fed the RPS-containing diets compared with those fed the NC, irrespective of the RPS levels or the form of RPS. However, there were no differences (P > 0.10) in visceral organ weights, growth performance, and digestibilities of DM, CP, Ca, and P among treatments. The results of this experiment indicate that supplementing a weaner pig diet with at least 0.5% RPS independent of mode of delivery has the potential to enhance outcomes characteristic of a functional gut in weaned pigs without adverse effects on growth.

Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post-weaning diarrhoea without using in-feed antimicrobial compounds.

For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic-resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post-weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level.

Standardized ileal amino acid digestibility in egg from hyperimmunized hens fed to weaned pigs.

The study was conducted to determine the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in egg from hens hyperimmunized with Escherichia coli K88 antigens (EGG) fed to weaned pigs. Spray dried porcine plasma (SDPP) was included for comparison. Eight barrows (Yorkshire-Landrace × Duroc; initial BW of 17 ± 1 kg) were fitted with a T-cannula at the distal ileum and fed 2 diets in a completely randomized design to give 4 replicates per diet. The diets were corn (Zea mays) starch based with either EGG or SDPP as the sole source of protein and were formulated to contain 130 g/kg CP. At the end of the study, a 50 g/kg casein diet was fed to all pigs (n = 8) to quantify endogenous N and AA losses to determine SID. Titanium dioxide (3 g/kg) was included in the diets as an indigestible maker. Each period lasted for 7 d. Pigs were adapted to their respective diets for 5 d followed by 12 h of continuous ileal digesta collection on days 6 and 7. Daily feed allowance was set at 4% BW at the beginning of each period and offered in 2 equal portions at 0800 and 1600 h as a dry mash. Pigs had unlimited access to water via low pressure nipple drinkers. The AID (%) of CP and indispensable AA were lower (P < 0.05) in EGG compared with SDPP. The SID (%) of CP (82 vs. 96) and indispensable AA were lower (P < 0.05) in pigs fed EGG compared with SDPP. In conclusion, the average AID and SID of N and indispensable AA in EGG are lower than in SDPP when fed at high levels.

Feeding a diet with decreased protein content reduces indices of protein fermentation and the incidence of postweaning diarrhea in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli.

This study evaluated the effect of feeding low protein (LP) diets for 7 or 14 d after weaning or a high protein (HP) diet for 14 d after weaning on postweaning diarrhea (PWD), indices of protein fermentation, and production in pigs infected or not infected per os with an enterotoxigenic strain of Escherichia coli. A total of 72 female pigs weaned at aged 21 d with initial BW of 5.9 +/- 0.12 kg were used in a 3 x 2 factorial arrangement of treatments. The factors were 3 feeding regimens associated with different combinations of feeding duration and diet CP level: (i) HP diet (256 g of CP/kg) fed for 14 d after weaning, (ii) LP diet (175 g of CP/kg) fed for 7 d after weaning, and (iii) LP diet fed for 14 d after weaning; and infection or noninfection with an enterotoxigenic strain of E. coli (10(7) cfu/mL, serotype O149:K91:K88) at 72, 96, and 120 h after weaning. The LP diets were fortified with crystalline Ile and Val to achieve an ideal AA pattern. A second-stage diet (213 g of CP/kg) was fed to pigs at the conclusion of each feeding regimen, and the study finished 4 wk after weaning. None of the diets contained antimicrobials. Feeding the LP diets decreased (P < 0.001) plasma urea nitrogen, fecal ammonia nitrogen concentrations, and the incidence of PWD, but increased (P = 0.001) fecal DM content compared with pigs fed HP in the 2-wk period after weaning. Infection increased shedding of beta-hemolytic E. coli (P < 0.001), the incidence of PWD (P < 0.001), and fecal ammonia nitrogen concentrations (P < 0.01), but did not interact with feeding regimen, after weaning. Pigs challenged with E. coli grew more slowly (P < 0.001) and had decreased G:F (P < 0.01) compared with nonchallenged pigs in the 4-wk period after weaning. Feeding an LP diet for 7 or 14 d after weaning markedly reduced the incidence of PWD after infection with beta-hemolytic E. coli. Infection was associated with decreased indices of protein fermentation in the distal gastrointestinal tract but did not compromise the growth of weaner pigs in the 4-wk period after weaning.

Variation in digestible energy content of Australian sweet lupins (Lupinus angustifolius L.) and the development of prediction equations for its estimation.

Sixty-three male pigs (Landrace x Large White) weighing 49.5 +/- 0.40 kg were used to (1) examine the variation in DE content of Lupinus angustifolius L. in relation to variety and geographical growing region and (2) establish prediction equations for DE content from physical and chemical composition. The pigs were randomly allocated to a 4 x 2 factorial treatment design with respective factors being 4 varieties (cv. Belara, Coromup, Mandelup, and Tanjil) and 2 growing locations (northern and southern agricultural areas of Western Australia). In addition, a wheat control diet was fed as a reference for calculation of lupin DE content. The lupins were ground through a hammer mill fitted with a 4-mm screen to a mean particle size of 888 mum. Pigs were fed their respective experimental diets at 3 times maintenance energy level [3 x (0.458 x BW(0.75))/diet DE] in the study. The DE content of lupins ranged from 13.3 to 15.7 MJ/kg with a mean value of 14.2 MJ/kg. Variety of lupins affected (P < 0.01) the DE content, and lupins grown in the northern agricultural region had a greater DE content than the same lupins grown in the southern agricultural area (P < 0.01). Although the variation in DE content of lupins was mostly caused by significantly greater DE content of cv. Coromup grown in the northern agricultural region, the results suggest that genetic and environmental conditions during the growth of lupins have a significant impact on the utilization of energy in grower pigs. Simple regression analysis showed that prediction of DE content was possible from the proportion of hulls [R(2) = 0.88, residual SD (RSD) = 1.116, P < 0.001], 1,000-seed weight (R(2) = 0.77, RSD = 1.092, P < 0.01), and soluble arabinoxylan content (R(2) = 0.64, RSD = 1.072, P < 0.05). Multiple regression analysis showed that adding total nonstarch polysaccharide (R(2) = 0.96, RSD = 1.187, P < 0.01) and soluble nonstarch polysaccharide (R(2) = 0.95, RSD = 1.200, P < 0.01) to the equation along with the proportion of hull and 1,000-seed weight significantly improved the accuracy of prediction. Results indicate that the DE content of lupins varies by up to 2.4 MJ/kg and that the DE content can be predicted with a good degree of accuracy using physical and chemical characteristics.

Infestation status of head louse and treatment with lindane shampoo in children of primary school and kindergarten in Chinju-shi, Kyongsangnam-do, Korea.

The infestation status of head louse among children attending primary schools and kindergartens in Chinju-shi, Kyongsangnam-do, Korea, was investigated between June and July 1999. Out of 2,288 children examined, 3.9% of boys (48/1,242) and 23.5% of girls (246/1,046) were infested with nits or adult/nymphs of lice. The effectiveness of lindane shampoo (1% gamma benzene hexachloride solution) was evaluated after one or two time applications to all the children infested. The negative conversion rate of pediculosis was 93.5%. Effective control measures are needed to control and prevent such ectoparasite infestation amongst children.