Feeding habits and the influence of pellet diameter on the feeding responses of the flathead grey mullet (Mugil cephalus) in captivity

The feeding habits and effect of the diameter of pelleted feeds on the feeding responses of wild juvenile and adult flathead grey mullet (Mugil cephalus) in captivity were examined. Optimal pellet size for feeding was defined according to the behavioural responses and ingestion of pellets with different diameters (2, 4, 6, 8 mm) that were dropped into the tank in a random sequence. Larger pellets (6 and 8 mm) were more attractive (lower reaction time, high percentage of capture), but the small to medium-sized pellets (2 and 4 mm) were consumed the most. The optimal size was the 2- and 4-mm pellet diameter for juvenile individuals (365.50 ± 36.90 g; 28.8 ± 0.84 cm) and the 4-mm diameter pellet for adults (937.49 ± 146.54 g; 40 ± 1.12 cm). The preferred feeding area of adult mullet was also studied to estimate preference in relation to pellet characteristics such as floating or sink. Two pellet types, floating or sinking, were offered simultaneously in the water column: at the surface, mid-water column and bottom of the tank. The flathead grey mullet had a preference to feed in the mid-water column and the bottom of the tanks indicating that sinking or slow-sinking pellets would be the optimal feed type in relation to mullet feeding behaviour.

PSI-33 Effect of conditioning temperature and pellet diameter on nursery pig growth performance

A total of 350 nursery pigs (initially 7.6 kg BW) were used in a 28-d trial to evaluate the effects of conditioning temperature and pellet diameter on nursery pig performance. Pigs were randomly assigned to 1 of 7 treatments with 10 pens/treatment and 5 pigs/pen. The 7 treatments were arranged in a 2×3 factorial design plus a mash control, with the factors of pellet diameter (4.0 mm vs. 4.8 mm), and conditioning temperature (low, medium, vs. high). Phase 1 conditioning temperatures were 54°C, 66°C, and 77°C, while phase 2 conditioning temperatures were 54°C, 71°C, and 88°C for low, medium, and high, respectively. Pigs were fed phase 1 from d 0 to 14, which contained 10% spray dried whey, while phase 2 was fed from d 14 to 28, which did not contain milk products. Pig weights and feed disappearance were recorded weekly to determine ADG, ADFI, and G:F. Data were analyzed using the GLIMMIX procedure of SAS with pen as the experimental unit. Pellet diameter did not impact (P > 0.05) nursery pig growth performance. Pigs fed pelleted diets had greater (P < 0.05) G:F than those fed mash diets. During phase 1 and overall, there were no significant (P > 0.05) interactive or main effects. However, conditioning phase 2 diets at lower temperatures improved (P < 0.05) ADG and G:F than medium and high conditioning temperatures. In conclusion, pelleting improves nursery pig feed efficiency. To maximize nursery pig feed efficiency, phase 2 diets should be conditioned at relatively low temperatures.

Influence of feed ingredients with pellet-binding properties on physical pellet quality, growth performance, carcass characteristics and nutrient retention in broiler chickens

The influence of inclusion of pellet binder on physical pellet quality, growth performance, carcass characteristics and total tract apparent retention of nutrients was examined. Broiler starter (Days 1–21, pellet diameter: 2.5 mm) and finisher (Days 22–42, pellet diameter: 4 mm) diets were formulated and then allocated to one of the seven treatments including control diet, and diets including sodium bentonite (10 and 20 g/kg), wheat gluten (10 and 20 g/kg) and wheat (100 and 200 g/kg). All ingredients used as a pellet binder significantly (P < 0.05) increased the pellet-durability index compared with control diet. Wheat gluten and wheat at both inclusion rates were significantly (P < 0.05) more efficient than was sodium bentonite in improving pellet hardness. From Day 1 to Day 42, chickens fed 10 g/kg wheat gluten and 100 and 200 g/kg wheat gained significantly (P < 0.05) more weight than did control. During starters, birds fed 200 g/kg wheat showed the highest feed intake (P < 0.05). On Day 42, all the pellet binders resulted in a heavier heart weight than in the control (P < 0.05). At Day 21, the length of ileum was significantly (P < 0.05) higher in birds fed 10 and 20 g/kg sodium bentonite, 10 g/kg wheat gluten and 200 g/kg wheat, but at Day 42, it was greater in birds fed 20 g/kg wheat gluten and 200 g/kg wheat than in those fed the control diet. Inclusion of wheat gluten (10 and 20 g/kg) and wheat (100 and 200 g/kg) increased (P < 0.05) fat apparent retention. Birds fed 20 g/kg wheat gluten had a significantly (P < 0.05) higher total tract apparent retention of crude fibre, also calcium apparent retention improved by wheat gluten inclusion at concentrations of 10 and 20 g/kg compared with control (P < 0.05). Overall, inclusion of 10 g/kg wheat gluten, and 100 and 200 g/kg of wheat improved physical pellet quality and weight gain in broilers.

Effects of Pellet Processing Parameters on Pellet Quality and Nursery Pig Growth Performance

During the pelleting process, conditioning temperature can influence nutrient availability and pellet durability index (PDI). However, the impact of conditioning temperature on nursery pig growth performance is variable. Therefore, the objectives of two experiments were to: (1) compare moisture percentage among three pellet mill series, and (2) quantify growth performance differences in nursery pigs due to diet form (mash vs. pelleted), conditioning temperature (low, medium, and high), and pellet diameter (4.0 mm and 5.2 mm). Experiment 1 was a 3 × 4 factorial design with three pellet mill series of decreasing capacity (medium, small, and experimental-scale; California Pellet Mill Co., Crawfordsville, Indiana, for a medium, small, and experimental pellet mill, respectively) that produced samples collected at four locations (initial, post-conditioner, post-die, and post-cooling). Three runs were completed on each pellet mill, with the shutdown of the pellet mill indicating the end of a run. Three samples were collected from each location per run, for a total of 36 samples. Experiment 2 used 350 nursery pigs (DNA 200 × 400; initially 7.6 kg) in a 28 d experiment fed two phases, with a phase change at day 14. Seven treatments were arranged in a 2 × 3 factorial design plus an unpelleted mash control, with the factors of pellet diameter (4.0 mm and 5.2 mm) and conditioning temperature (low, medium, and high). Data were analyzed using the GLIMMIX procedure of SAS (version 9.4). In experiment 1, there was a significant pellet mill × location interaction (p = 0.012) for moisture percentage. Because moisture is added via steam at the conditioner, only the conditioning location results are described. Regardless of pellet mill type, moisture was highest in conditioned samples. However, conditioned samples from the experimental-sized pellet mill had over 1% greater (p < 0.05) moisture than samples from the medium and small pellet mills. This increase in moisture is one reason why higher (p < 0.05) PDI values were found in pellets from the experimental pellet mill compared to the medium and small pellet mills. In experiment 2, increasing conditioning temperature improved (p < 0.0001) PDI. The interaction of pellet diameter × conditioning temperature did not impact (p > 0.10) overall nursery pig feed efficiency (G:F). However, for overall G:F, both main effects tended to be significant (p < 0.10), which was caused by pigs having greater (p < 0.05) G:F when fed larger-diameter pellets conditioned at a low temperature, compared to pigs fed smaller-diameter pellets conditioned at a high temperature. Regardless of parameter, pigs fed pelleted diets had 4.5% greater (p < 0.05) G:F than those fed mash diets. In summary, pellet mill size is important to consider when evaluating factors that impact pellet quality, such as percentage moisture. Increasing conditioning temperature is one method to improve PDI, but there was a tendency to reduce nursery pig G:F when feeding two phases of diets in a 28 d study. In conclusion, conditioning feed at lower temperatures may improve nursery pig G:F when starting pigs on a new diet. Keywords: Moisture, Pelleting, Starch.

Gaseous Emissions after Soil Application of Pellet Made from Composted Pig Slurry Solid Fraction: Effect of Application Method and Pellet Diameter

The study aimed at determining ammonia and GHG emissions from soil fertilized with pellets made from composted pig slurry solid fraction and to evaluate the effects of pellet diameter and pellet application method on gaseous emissions. A laboratory scale experiment was carried out investigating two composts: pig slurry solid fraction compost (SSFC) and pig slurry solid fraction mixed with wood chips compost (WCC). The two composts were pelettized in two different diameters—6 and 8 mm—by means of mechanical pelletizer. In total, eight fertilized treatments plus one unfertilized control were included in the experiment. The investigated pellets were applied at the same nitrogen rate (equivalent to 200 kg ha−1) using two different methods (on soil surface and incorporated into the soil). Ammonia (NH3) emission was monitored immediately after pellet application, while nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) were measured on a 57-day incubation period. As expected, ammonia volatilization was not detected from any of the treatments investigated. At the end of the experiment, the cumulative amounts of N2O, CO2 and CH4 ranged from 2.70 mg N-N2O m−2 to 24.30 mg N-N2O m−2, from 601.89 mg C-CO2 m−2 to 1170.34 mg C-CO2 m−2 and from 1.22 mg C-CH4 m−2 to 1.31 mg C-CH4 m−2, respectively. The overall results of the investigation highlighted that application on the soil surface reduced nitrous oxide emission, while the carbon dioxide emission increased significantly with smaller pellet diameter.

Effect of Catalyst Pellet-Diameter and Basicity on Transesterification of Soybean Oil into Biodiesel using K2O/CaO-ZnO Catalyst over Hybrid Catalytic-Plasma Reactor

This research is aimed to study the effect of catalyst pellet-diameter and catalyst basicity on the transesterification process of soybean oil into biodiesel over a hybrid catalytic-plasma reactor. Various catalyst diameters (3, 5, and 7 mm) were tested in this reaction system. Catalyst basicity was also examined by comparing fresh and used catalyst as well as with and without K2O promoter. All catalysts testing were performed in a hybrid plasma-catalytic reactor (dielectric barrier discharge – DBD type). From the results, the synergistic effects roles of the catalyst and the plasma in the transesterification process are important, in which the energetic electrons within plasma assist the reaction on the catalyst surface by an exciting bonded electron. The catalyst basicity was influenced by the composition of CaO on the catalyst as well as roles of the alkaline K2O promoter. Catalyst basicity is important in producing biodiesel with high performance. Yield of fatty acid alkyl ester (FAAE) or biodiesel is slightly influenced by the catalyst diameter within the range of diameter studied.