Four isocaloric-isonitrogenous diets containing 0, 50, 100 and 190 g/kg corn protein concentrate (CPC) as replacement for dietary fish meal were fed to Nile tilapia Oreochromis niloticus fingerlings for 8 weeks. Tilapia growth parameters were not significantly (p > .05) different in fish fed diets with 0, 50 and 100 g/kg CPC and found to be superior compared to those fed on 190 g/kg CPC. Fish dressing ratios and body composition were similar among all treatments. The electron microscope indicated that the stomach size of control fish was slightly smaller and the wall was thinner while the stomach of the fish fed all other levels of CPC undergone a remarkable size increase and their walls were thicker after feeding diets with CPC. Total aerobic bacterial and coliform counts were significantly decreased in fish intestine when fed diets with 100 and 190 g/kg CPC compared with fish fed diets with 0 g/kg or 50 g/kg CPC.This study indicates that it is possible to replace up to 534 g/kg of dietary fish meal in tilapia fingerlings using 100 g/kg of CPC without any negative effect on fish growth and proximate body composition.
K E Y W O R D Sbacterial populations, commercial diets, corn protein concentrate, fish meal, Nile tilapia
The expansion in date processing has produced a large quantity of date pits Phoenix dactylifera L.: var. ruzeiz that could be used in animal feeds. To evaluate the nutritional value of date pits and their sprouts, two growth trials were conducted using semi‐purified diets and fingerling tilapia Oreochromis niloticus (L.). In the first trial, four isocaloric‐isonitrogenous diets containing different levels (0, 15, 30, and 45%) of date pits as a replacement for corn starch were fed to three replicate groups of fingerlings with a mean initial weight of 3.09 ± 0.10 g/fish. At the conclusion of the 9‐wk growth trial, final weight gain, feed conversion, specific growth rate and PER were significantly reduced in fish fed diets with all levels of date pits as compared to those fed the control diet (without date pits). However, there were no significant differences in these parameters for fish fed diets contained 15%, 30%, or 45% date pits. Body crude fat was gradually reduced as the level of date pits in the test diets was increased. Consequently, body moisture, crude protein and total ash were proportionally increased. In second trial, three isocaloric‐isonitrogenous diets containing 0% date pits (control diet), 15% date pits sprouted for 15 d, and 15% date pits sprouted for 30 d were fed to triplicate groups of tilapia with mean initial weight 2.60 t 0.09 g/ fish) for 9 wk. Growth rates and body composition of fish fed diets containing date pits that were sprouted for 15 or 30 d were similar to that of those fed the control diet. Under the reported conditions the inclusion of sprouted date pits did not affect growth and body composition, whereas nonsprouted date pits negatively influenced fish performance.
Five isocaloric-isonitrogenous diets containing 0, 150, 300, 450 and 600 g kg )1 of fungi Trichoderma reesei-degraded date pits (DDP), as a replacement for dietary corn, were fed to triplicate groups of Nile tilapia Oreochromis niloticus L. fingerlings (1.88 g initial weight), for 9 weeks, in 70 L fibreglass tanks. Each tank was considered as an experimental unit and was part of a water recirculating system utilizing filtered and aerated ground well water (24 ± 3°C). Tilapia growth performance, namely, weight gain, feed conversion, specific growth rate and protein efficiency ratio were similar and superior in fish fed diets containing 150 and 300 g kg )1 DDP, when compared with those fish fed the other diets. Fish fed the control diet with 450 g kg )1 DDP had better growth efficiency performance than those fed diets containing 0 and 600 g kg )1 . Fish fed the diet with 600 g kg )1 DDP were inferior to all other groups. Tilapia body composition was affected by increasing DDP level in the diets as body fat was decreased, while body moisture was increased. In conclusion, DDP could replace 300 g kg )1 of dietary corn with better growth results. Further increase of date pits replacements to 450 g kg )1 will affect growth performance, when compared with the control.
KEY WORDS
Four isocaloric–isonitrogenous rations containing 0%, 15%, 30% and 51% of ground barley seeds as a replacement for dietary corn were fed to three replicate groups of Oreochromis niloticus (Linnaeus) fingerlings with a mean initial weight of 3.5 g. The randomly selected fish were tested for 9 weeks in 60 L circular tanks. Each tank was considered as an experimental unit. The tanks were put together in a water recirculating system using filtered and aerated ground well water (24 ± 3 °C). Tilapia weight gain, feed conversion, specific growth rate and protein efficiency ratio were similar in fish fed diets containing 15% and 30% barley and were superior to those fed diets containing 0% control and 51% barley. There were no differences between tilapia fed diets containing 0% and 51% barley. Body moisture, crude fat, crude protein and total ash did not change as the level of barley in the feeds was increased.
The current study aims to assess the effect of non-degraded date pits (NDDP) and degraded date pits (DDP) in broilers’ diets on gut microbiota and growth performance. The degradation of date pits (DP) occurred via the cellulolytic fungus Trichoderma reesei by a solid-state degradation procedure. One-day-old Brazilian broilers were allocated into six dietary groups: (1) maize–soy diet, (2) maize–soy diet with oxytetracycline (20%, 50 g 100 kg−1), (3) maize–soy diet with 5% NDDP, (4) maize–soy diet with 10% NDDP, (5) maize–soy diet with 5% DDP, and (6) maize–soy diet with 10% DDP. At the end of the trial, the total count of bacteria was significantly (p < 0.05) less in broilers fed 10% DDP diet (treatment 6) compared with the control group (treatment 1). In addition, DDP and oxytetracycline control diets have a similar diminishing effect on total bacterial counts and the populations of Salmonella, Campylobacter, Shigella spp., and Escherichia coli. Over 35 days of trial, weight gains were similar among the six dietary groups. Our results showed that DDP and control diets have a similar effect on growth performance. The feed conversion ratio (FCR) was poorer in broilers fed NDDP diets than other treatments. The European Production Efficiency Index (EPEI) was greater with 5% and 10% DDP than those fed NDDP at the same levels, with no significant variance from the control and antibiotic-supplemented diet (treatment 2). Overall, it can be suggested that maintaining 10% of DDP can partly replace dietary maize while also serves as a gut health enhancer and thus a growth promoter in the diet for broilers.
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