Two experiments were conducted separately to study the effect of astaxanthin on production performance and egg quality in laying hens and meat quality in finishing pigs. In Experiment 1, four hundred Brown Hy-Line layers, 26 weeks of age, were randomly divided into five treatments according to a single factorial arrangement. Each treatment had four replicates comprising 20 birds each. The dietary treatments were: 0, 0.7, 0.9, 1.1 and 1.3 ppm of astaxanthin fed for 14 days. Then all the birds were fed an astaxanthin-free diet (0 ppm astaxanthin) for an additional 7 days. The results showed that dietary astaxanthin had no significant effect on layer production performance. There was no significant effect (p>0.05) on egg weight, yolk height and Haugh unit (HU) with increasing dietary astaxanthin level and increased storage time. Yolk color was linearly increased (p<0.01) with the increasing dietary astaxanthin level and significantly decreased with the increasing storage time (p<0.05). The TBARS value in yolk decreased linearly (p<0.05) with increasing amount of dietary astaxanthin and storage time. When the diets were replaced with the astaxanthin-free feeds, all parameters concerning egg quality decreased with increasing days of measurement, especially the yolk color, and HU significantly decreased (p<0.05). In experiment 2, thirty-six barrows (L×Y×D), 107±3.1 kg BW, were randomly divided into three treatments according to a single factorial arrangement. Each treatment had three replicates comprising 4 pigs each. The dietary treatments were: 0, 1.5 and 3.0 ppm of astaxanthin fed for 14 days. The results showed that dietary astaxanthin had no significant effects on production performance. There was a linear effect (p<0.05) on dressing percentage, backf.at thickness and loin muscle area with increasing dietary astaxanthin level. There were no significant effects (p>0.05) on the TBARS value, drip loss, meat color, marbling and L*, a*, b* values. Cholesterol concentration in meat was not affected by dietary addition of astaxanthin. It could be concluded that astaxanthin supplementation was beneficial to improve egg yolk color; egg quality during storage and it also could improve the meat quality of finishing pigs.

An experiment was conducted in weanling pigs (Landrace x Yorkshire x Duroc) to evaluate the effects of dietary iron levels on growth performance, hematological status, liver mineral concentration, fecal microflora, and diarrhea incidence. One hundred and forty-four piglets (initial BW 5.96 +/- 0.93 kg) were randomly allotted to one of the four dietary treatments on the basis of their body weights. The basal diets for each phase (phase 1: days 0 to 14; phase 2: days 15 to 28) were formulated to contain minimal Fe and then supplemented with gradient levels of Fe (0, 50, 100, and 250 mg/kg) from ferrous sulfate. Feces were collected on days 14 and 28 and used for the analysis of microbial count and trace minerals. Eight piglets from each treatment (two piglets per pen) were bled at 0, 7, 14, 21, and 28 days to determine their hematological and plasma Fe status. In addition, two piglets from each pen (eight piglets per treatment) were killed at days 14 and 28 to determine liver mineral concentrations. Pigs fed supplemental 250 ppm Fe showed lowest overall average daily gain (linear, p = 0.036). Diarrhea incidence was linearly increased (p < 0.001) with supplemental Fe level. On days 14, coliform population in normal feces was increased (p = 0.036) linearly with supplemental Fe level, and there were higher (p = 0.043) coliform population and lower (p < 0.001) Bifidobacterium spp. in the diarrhea feces. Supplemental Fe linearly (p < 0.05) improved the total red blood cells, hemoglobin, plasma, and liver (p = 0.109) Fe status of pigs and also increased (linear and quadratic, p < 0.001) the fecal excretion of Fe on days 14 and 28. It is concluded that increasing the dietary iron levels in piglets improved their hematological status and liver Fe content; however, higher dietary Fe levels might also be associated with the increased diarrhea incidence.

Two experiments were conducted to evaluate potato protein (PP, experiment 1) and refined PP (RPP, experiment 2) obtained from Gogu valley tubers as an antimicrobial agent in broiler diets. In both the experiments, 1-d-old male Ross 308 chicks were allotted to 5 treatments and performance, nutrient retention, and microbial populations in excreta and cecum were studied. Dietary treatments were as follows: basal diet (negative control, NC), basal diet with antibiotic (positive control, PC, 10 mg/kg of avilamycin), and low, medium, or high levels of PP (0.25, 0.50, and 0.75%, respectively, in experiment 1) or RPP (200, 400, and 600 mg/kg, respectively, in experiment 2). The overall gain and retention of DM (d 20 to 21) and CP (d 20 to 21 and d 41 to 42) were greater in birds fed PC and high PP diets than birds fed the NC diet. Population of total aerobic bacteria and coliforms was lowest in the cecum and excreta of birds fed the PC diet and highest in birds fed the NC diet. An increase in dietary PP linearly improved BW gain, feed intake, and feed conversion ratio during starter phase and overall BW gain. Also, there was linear improvement in retention of DM (d 20 to 21) and CP (d 20 to 21 and d 41 to 42) and reduced populations of total aerobic bacteria and coliforms in the cecum (d 42) and excreta (d 28 and 42) due to an increase in dietary PP. In the second experiment, the PC diet and diets with increasing levels of RPP had no effect on performance and nutrient retention. Birds fed the PC diet had the lowest microbial population in excreta and cecum, whereas the population of total aerobic bacteria and coliforms in excreta and cecum decreased (linear, P < 0.05) as the level of RPP was increased in the diet. These results suggest that both PP and RPP obtained from Gogu valley potato tubers have in vivo antimicrobial activity.

Three experiments were conducted to determine the feed processing method best suited for early and conventionallyweaned pigs, and to investigate the effects of different extrusion temperatures on ileal digestibility of amino acids in diets containing different protein sources. In exp.1, a total of 108 pigs (Landrace×Yorkshire×Duroc; 24 d of age and 7.60 kg average body weight) were alloted on the basis of sex, weight and ancestry to three treatments in a randomized complete block design. Feed processing methods used were mash (M), simple pellet (SP), and expanded pellet (EP). In exp. 2, a total of 96 pigs (Landrace×Yorkshire×Duroc; 14 d of age) were allotted on the basis of sex, weight, and ancestry to three treatments in a randomized complete block design. Diets were mash (M), expanded pellet (EP), and expanded pellet crumble (EPC). In exp. 3, a study was designed to investigate the effect of different extrusion temperatures (100, 120, and 140°C) over the control (untreated) on the ileal digestibility of amino acids in diets containing protein sources such as spray-dried plasma protein (SDPP), whey protein concentrate (WPC), and fish meal (FM). Results in exp.1 showed that ADG, ADFI and the F/G ratio of pigs fed the SP diet were improved (p<0.05) compared with those fed the M or the EP diets, but the digestibility of nutrients was not different (p>0.05) among the treatments. In exp. 2, pigs fed expanded pellet treatments (EP or EPC) had a significantly improved (p<0.05) F/G ratio compared to the pigs fed the M diet which was primarily attributed to the significant reduction (p<0.05) in ADFI, but the overall growth rate of pigs fed expanded pellet diets was not improved. In exp. 3, there was a significant interaction effect (p<0.05) between the extrusion temperature and protein source on the ileal digestibility of amino acids. With an extrusion temperature of 100°C, the ileal digestibility of Lys, Val, Gly and Ser was significantly lower in the diet containing WPC compared to the diet containing SDPP. Increasing the temperature to 120°C led to significant differences (p<0.05) in the digestibility of Thr and Tyr between diets containing WPC and SDPP. Regardless of extrusion temperatures, the weaned pigs' diet containing either SDPP or FM had significantly higher Lys, Phe, Thr, Val, and Gly digestibility relative to the WPC diet. Results of the present study suggest that simple pelleting of diets containing protein sources such as whey protein concentrate, spray-dried plasma protein and fish meal would be better than the extruded or expanded pellet diets. Extruder or expander processing of weaned pigs' feed could reduce palatability and ileal digestibility of several amino acids and therefore may be responsible for a negative growth response in weaned pigs.